X-Git-Url: https://git.grml.org/?p=grml2usb.git;a=blobdiff_plain;f=grml2usb;h=afb983cc559dda86238c3667479e201eb42e8058;hp=737c68a9ba376c7aea7e845c2adf5440c486cece;hb=7ca80ac0f15e6657deac53d5a211a176f2c6f12c;hpb=100193b24b57c98c475f58484764d1b945666ff4

diff --git a/grml2usb b/grml2usb
index 737c68a..afb983c 100755
--- a/grml2usb
+++ b/grml2usb
@@ -5,7 +5,7 @@
 grml2usb
 ~~~~~~~~
 
-This script installs a grml system (either a running system or ISO[s]) to a USB device
+This script installs a Grml system (either a running system or ISO[s]) to a USB device
 
 :copyright: (c) 2009, 2010, 2011 by Michael Prokop <mika@grml.org>
 :license: GPL v2 or any later version
@@ -13,25 +13,42 @@ This script installs a grml system (either a running system or ISO[s]) to a USB
 
 """
 
+from __future__ import print_function
 from optparse import OptionParser
 from inspect import isroutine, isclass
-import datetime, logging, os, re, subprocess, sys, tempfile, time, os.path
+import datetime
 import fileinput
 import glob
-import uuid
+import logging
+import os
+import os.path
+import re
 import struct
+import subprocess
+import sys
+import tempfile
+import time
+import uuid
+import shutil
 
 # The line following this line is patched by debian/rules and tarball.sh.
-PROG_VERSION='***UNRELEASED***'
+PROG_VERSION = '***UNRELEASED***'
 
 # global variables
-MOUNTED = set()  # register mountpoints
-TMPFILES = set() # register tmpfiles
-DATESTAMP = time.mktime(datetime.datetime.now().timetuple()) # unique identifier for syslinux.cfg
-GRML_FLAVOURS = set() # which flavours are being installed?
+MOUNTED = set()   # register mountpoints
+TMPFILES = set()  # register tmpfiles
+DATESTAMP = time.mktime(datetime.datetime.now().timetuple())  # unique identifier for syslinux.cfg
+GRML_FLAVOURS = set()  # which flavours are being installed?
 GRML_DEFAULT = None
 UUID = None
 SYSLINUX_LIBS = "/usr/lib/syslinux/"
+GPT_HEADER = "\x55\xaa\x45\x46\x49\x20\x50\x41\x52\x54"  # original GPT header
+GRUB_INSTALL = None
+
+RE_PARTITION = re.compile(r'([a-z/]*?)(\d+)$')
+RE_P_PARTITION = re.compile(r'(.*?\d+)p(\d+)$')
+RE_LOOP_DEVICE = re.compile(r'/dev/loop\d+$')
+
 
 def syslinux_warning(option, opt, value, opt_parser):
     """A helper function for printing a warning about deprecated option
@@ -41,6 +58,7 @@ def syslinux_warning(option, opt, value, opt_parser):
                      "is grml2usb's default. Continuing anyway.\n")
     setattr(opt_parser.values, option.dest, True)
 
+
 # if grub option is set, unset syslinux option
 def grub_option(option, opt, value, opt_parser):
     """A helper function adjusting other option values
@@ -50,10 +68,10 @@ def grub_option(option, opt, value, opt_parser):
     setattr(opt_parser.values, 'syslinux', False)
 
 # cmdline parsing
-USAGE = "Usage: %prog [options] <[ISO[s] | /live/image]> </dev/sdX#>\n\
+USAGE = "Usage: %prog [options] <[ISO[s] | /lib/live/mount/medium]> </dev/sdX#>\n\
 \n\
-%prog installs grml ISO[s] to an USB device to be able to boot from it.\n\
-Make sure you have at least one grml ISO or a running grml system (/live/image),\n\
+%prog installs Grml ISO[s] to an USB device to be able to boot from it.\n\
+Make sure you have at least one Grml ISO or a running Grml system (/lib/live/mount/medium),\n\
 grub or syslinux and root access.\n\
 \n\
 Run %prog --help for usage hints, further information via: man grml2usb"
@@ -85,19 +103,27 @@ parser.add_option("--quiet", dest="quiet", action="store_true",
                   help="do not output anything but just errors on console")
 parser.add_option("--remove-bootoption", dest="removeoption", action="append",
                   help="regex for removing existing bootoptions")
+parser.add_option("--rw-blockdev", dest="rwblockdev", action="store_true",
+                  help="enforce read-write mode on involved block devices")
 parser.add_option("--skip-addons", dest="skipaddons", action="store_true",
                   help="do not install /boot/addons/ files")
+parser.add_option("--skip-bootflag", dest="skipbootflag", action="store_true",
+                  help="do not try to check whether the destination has the bootflag set")
 parser.add_option("--skip-grub-config", dest="skipgrubconfig", action="store_true",
                   help="skip generation of grub configuration files")
 parser.add_option("--skip-mbr", dest="skipmbr", action="store_true",
                   help="do not install a master boot record (MBR) on the device")
 parser.add_option("--skip-syslinux-config", dest="skipsyslinuxconfig", action="store_true",
                   help="skip generation of syslinux configuration files")
+parser.add_option("--skip-usb-check", dest="skipusbcheck", action="store_true",
+                  help="skip check to verify whether given device is removable")
 parser.add_option("--syslinux", dest="syslinux", action="callback", default=True,
                   callback=syslinux_warning,
                   help="install syslinux bootloader (deprecated as it's the default)")
 parser.add_option("--syslinux-mbr", dest="syslinuxmbr", action="store_true",
                   help="install syslinux master boot record (MBR) instead of default")
+parser.add_option("--tmpdir", dest="tmpdir", default="/tmp",
+                  help="directory to be used for temporary files")
 parser.add_option("--verbose", dest="verbose", action="store_true",
                   help="enable verbose mode")
 parser.add_option("-v", "--version", dest="version", action="store_true",
@@ -110,11 +136,22 @@ if not os.path.isdir(GRML2USB_BASE):
     GRML2USB_BASE = os.path.dirname(os.path.realpath(__file__))
 
 
+class HodorException(Exception):
+    """Throw exception if the exact error is not known and not fatal.
+
+    @Exception: message"""
+
+
 class CriticalException(Exception):
-    """Throw critical exception if the exact error is not known but fatal."
+    """Throw critical exception if the exact error is not known but fatal.
+
+    @Exception: message"""
+
+
+class VerifyException(Exception):
+    """Throw critical exception if there is an fatal error when verifying something.
 
     @Exception: message"""
-    pass
 
 
 # The following two functions help to operate on strings as
@@ -137,19 +174,36 @@ def string2array(s):
 def cleanup():
     """Cleanup function to make sure there aren't any mounted devices left behind.
     """
+    def del_failed(fn, filepath, exc):
+        msg = "Deletion of %s failed in temporary folder %s"
+        logging.warn(msg % (filepath, path))
 
     logging.info("Cleaning up before exiting...")
     proc = subprocess.Popen(["sync"])
     proc.wait()
 
-    try:
-        for device in MOUNTED:
+    for device in MOUNTED.copy():
+        try:
             unmount(device, "")
-        for tmpfile in TMPFILES:
-            os.unlink(tmpfile)
-    # ignore: RuntimeError: Set changed size during iteration
-    except RuntimeError:
-        logging.debug('caught expection RuntimeError, ignoring')
+            logging.debug('Unmounted %s' % device)
+        except StandardError:
+            logging.debug('RuntimeError while umount %s, ignoring' % device)
+
+    for tmppath in TMPFILES.copy():
+        try:
+            if os.path.isdir(tmppath) and not os.path.islink(tmppath):
+                # symbolic links to directories are ignored
+                # without the check it will throw an OSError
+                shutil.rmtree(tmppath, onerror=del_failed)
+                logging.debug('temporary directory %s deleted' % tmppath)
+                unregister_tmpfile(tmppath)
+            elif os.path.isfile:
+                os.unlink(tmppath)
+                logging.debug('temporary file %s deleted' % tmppath)
+                unregister_tmpfile(tmppath)
+        except StandardError:
+            msg = 'RuntimeError while removing temporary %s, ignoring'
+            logging.debug(msg % tmppath)
 
 
 def register_tmpfile(path):
@@ -191,7 +245,7 @@ def unregister_mountpoint(target):
 
 
 def get_function_name(obj):
-    """Helper function for use in execute() to retrive name of a function
+    """Helper function for use in execute() to retrieve name of a function
 
     @obj: the function object
     """
@@ -200,6 +254,17 @@ def get_function_name(obj):
     return obj.__module__ + '.' + obj.__name__
 
 
+def set_rw(device):
+    if not options.rwblockdev:
+        return
+
+    logging.debug("executing: blockdev --setrw %s", device)
+    proc = subprocess.Popen(["blockdev", "--setrw", device])
+    proc.wait()
+    if proc.returncode != 0:
+        raise Exception("error executing blockdev on %s" % device)
+
+
 def execute(f, *exec_arguments):
     """Wrapper for executing a command. Either really executes
     the command (default) or when using --dry-run commandline option
@@ -243,48 +308,95 @@ def get_defaults_file(iso_mount, flavour, name):
     """
     bootloader_dirs = ['/boot/isolinux/', '/boot/syslinux/']
     for directory in bootloader_dirs:
-        for name in name, \
-        "%s_%s" % (get_flavour_filename(flavour), name):
+        for name in name, "%s_%s" % (get_flavour_filename(flavour), name):
             if os.path.isfile(iso_mount + directory + name):
                 return (directory, name)
-    return ('','')
+    return ('', '')
+
 
-def search_file(filename, search_path='/bin' + os.pathsep + '/usr/bin'):
+def search_file(filename, search_path='/bin' + os.pathsep + '/usr/bin', lst_return=False):
     """Given a search path, find file
 
     @filename: name of file to search for
-    @search_path: path where searching for the specified filename"""
-    file_found = 0
+    @search_path: path where searching for the specified filename
+    @lst_return: return list of matching files instead one file"""
     paths = search_path.split(os.pathsep)
-    current_dir = '' # make pylint happy :)
+    current_dir = ''  # make pylint happy :)
+    retval = []
 
     def match_file(cwd):
         """Helper function ffor testing if specified file exists in cwd
 
         @cwd: current working directory
         """
-        return  os.path.exists(os.path.join(cwd, filename))
+        return os.path.exists(os.path.join(cwd, filename))
 
     for path in paths:
         current_dir = path
         if match_file(current_dir):
-            file_found = 1
-            break
+            retval.append(os.path.abspath(os.path.join(current_dir, filename)))
+            if not lst_return:
+                break
         # pylint: disable-msg=W0612
         for current_dir, directories, files in os.walk(path):
             if match_file(current_dir):
-                file_found = 1
-                break
-    if file_found:
-        return os.path.abspath(os.path.join(current_dir, filename))
+                retval.append(os.path.abspath(os.path.join(current_dir, filename)))
+                if not lst_return:
+                    break
+    if lst_return:
+        return retval
+    elif retval:
+        return retval[0]
     else:
         return None
 
 
 def check_uid_root():
     """Check for root permissions"""
-    if not os.geteuid()==0:
-        sys.exit("Error: please run this script with uid 0 (root).")
+    if not os.geteuid() == 0:
+        raise CriticalException("please run this script with uid 0 (root).")
+
+
+# for usage inside check_boot_flag
+def get_partition_for_path(path):
+    import parted
+
+    boot_dev, x = get_device_from_partition(path)
+
+    d = parted.getDevice(boot_dev)
+    disk = parted.Disk(d)
+    return disk.getPartitionByPath(path)
+
+
+def check_boot_flag(device):
+    boot_dev, x = get_device_from_partition(device)
+
+    try:
+        import parted
+        part = get_partition_for_path(device)
+        if part is None:
+            raise HodorException("parted could not find partition")
+        if part.getFlag(parted.PARTITION_BOOT):
+            logging.debug("bootflag is enabled on %s" % device)
+            return
+    except HodorException, e:
+        logging.info("%s, falling back to old bootflag detection", e)
+    except ImportError, e:
+        logging.debug("could not import parted, falling back to old bootflag detection")
+
+    with open(boot_dev, 'r') as image:
+        data = image.read(520)
+        bootcode = data[440:]
+        gpt_data = bootcode[70:80]
+
+        if gpt_data == GPT_HEADER:
+            logging.info("GPT detected, skipping bootflag check")
+        elif bootcode[6] == '\x80':
+            logging.debug("bootflag is enabled")
+        else:
+            logging.debug("bootflag is NOT enabled")
+            raise VerifyException("Device %s does not have the bootflag set. "
+                "Please enable it to be able to boot." % device)
 
 
 def mkfs_fat16(device):
@@ -316,7 +428,7 @@ def generate_isolinux_splash(grml_flavour):
 
 Some information and boot options available via keys F2 - F10. http://grml.org/
 %(grml_name)s
-""" % {'grml_name': grml_name} )
+""" % {'grml_name': grml_name})
 
 
 def generate_main_syslinux_config(*arg):
@@ -364,7 +476,6 @@ def generate_flavour_specific_syslinux_config(grml_flavour):
 
     @grml_flavour: name of grml flavour the configuration should be generated for"""
 
-
     return("""\
 menu begin grml %(grml_flavour)s
     menu title %(display_name)s
@@ -376,7 +487,7 @@ menu begin grml %(grml_flavour)s
     include %(grml_flavour)s_grml.cfg
     menu hide
 menu end
-""" % {'grml_flavour': grml_flavour, 'display_name' : grml_flavour.replace('_', '-') } )
+""" % {'grml_flavour': grml_flavour, 'display_name': get_flavour_filename(grml_flavour)})
 
 
 def install_grub(device):
@@ -391,43 +502,43 @@ def install_grub(device):
         device_mountpoint = tempfile.mkdtemp(prefix="grml2usb")
         register_tmpfile(device_mountpoint)
         try:
-            try:
-                mount(device, device_mountpoint, "")
-
-                # If using --grub-mbr then make sure we install grub in MBR instead of PBR
-                if options.grubmbr:
-                    logging.debug("Using option --grub-mbr ...")
-                    if device[-1:].isdigit():
-                        grub_device = re.match(r'(.*?)\d*$', device).group(1)
-                    else:
-                        grub_device = device
-                else:
-                    grub_device = device
-
-                logging.info("Installing grub as bootloader")
-                for opt in ["", "--force" ]:
-                    logging.debug("grub-install --recheck %s --no-floppy --root-directory=%s %s",
-                                  opt, device_mountpoint, grub_device)
-                    proc = subprocess.Popen(["grub-install", "--recheck", opt, "--no-floppy",
-                                             "--root-directory=%s" % device_mountpoint, grub_device],
-                                            stdout=file(os.devnull, "r+"))
-                    proc.wait()
-                    if proc.returncode == 0:
-                        break
-
-                if proc.returncode != 0:
-                    # raise Exception("error executing grub-install")
-                    logging.critical("Fatal: error executing grub-install "
-                                     + "(please check the grml2usb FAQ or drop the --grub option)")
-                    logging.critical("Note:  if using grub2 consider using "
-                                     + "the --grub-mbr option as grub considers PBR problematic.")
-                    cleanup()
-                    sys.exit(1)
-            except CriticalException, error:
-                logging.critical("Fatal: %s", error)
+            # If using --grub-mbr then make sure we install grub in MBR instead of PBR
+            if options.grubmbr:
+                logging.debug("Using option --grub-mbr ...")
+                grub_device, x = get_device_from_partition(device)
+            else:
+                grub_device = device
+
+            set_rw(device)
+            mount(device, device_mountpoint, "")
+
+            logging.info("Installing grub as bootloader")
+            for opt in ["--", "--force"]:
+                set_rw(device)
+                set_rw(grub_device)
+                logging.debug("%s --recheck --no-floppy --target=i386-pc --root-directory=%s %s %s",
+                              GRUB_INSTALL, device_mountpoint, opt, grub_device)
+                proc = subprocess.Popen([GRUB_INSTALL, "--recheck",
+                                         "--no-floppy", "--target=i386-pc",
+                                         "--root-directory=%s" % device_mountpoint,
+                                         opt, grub_device],
+                                        stdout=file(os.devnull, "r+"))
+                proc.wait()
+                if proc.returncode == 0:
+                    break
+
+            if proc.returncode != 0:
+                # raise Exception("error executing grub-install")
+                logging.critical("Fatal: error executing grub-install " +
+                                 "(please check the grml2usb FAQ or drop the --grub option)")
+                logging.critical("Note:  if using grub2 consider using " +
+                                 "the --grub-mbr option as grub considers PBR problematic.")
                 cleanup()
                 sys.exit(1)
-
+        except CriticalException as error:
+            logging.critical("Fatal: %s", error)
+            cleanup()
+            sys.exit(1)
         finally:
             unmount(device_mountpoint, "")
             os.rmdir(device_mountpoint)
@@ -443,6 +554,8 @@ def install_syslinux(device):
         logging.info("Would install syslinux as bootloader on %s", device)
         return 0
 
+    set_rw(device)
+
     # syslinux -d boot/isolinux /dev/sdb1
     logging.info("Installing syslinux as bootloader")
     logging.debug("syslinux -d boot/syslinux %s", device)
@@ -461,14 +574,14 @@ def install_bootloader(device):
     if options.grub:
         try:
             install_grub(device)
-        except CriticalException, error:
+        except CriticalException as error:
             logging.critical("Fatal: %s", error)
             cleanup()
             sys.exit(1)
     else:
         try:
             install_syslinux(device)
-        except CriticalException, error:
+        except CriticalException as error:
             logging.critical("Fatal: %s", error)
             cleanup()
             sys.exit(1)
@@ -501,11 +614,12 @@ def install_mbr(mbrtemplate, device, partition, ismirbsdmbr=True):
     logging.info("Installing default MBR")
 
     if not os.path.isfile(mbrtemplate):
-        logging.critical("Error: %s can not be read.", mbrtemplate)
-        raise CriticalException("Error installing MBR (either try --syslinux-mbr or install missing file \"%s\"?)" % mbrtemplate)
+        logging.error('Error installing MBR (either try --syslinux-mbr or '
+            'install missing file "%s"?)', mbrtemplate)
+        raise CriticalException("%s can not be read." % mbrtemplate)
 
     if partition is not None and ((partition < 0) or (partition > 3)):
-        logging.warn("Cannot activate partition %d" % partition)
+        logging.warn("Cannot activate partition %d", partition)
         partition = None
 
     if ismirbsdmbr:
@@ -546,12 +660,14 @@ def install_mbr(mbrtemplate, device, partition, ismirbsdmbr=True):
                     mbrcode[463:478] + actives[2] + \
                     mbrcode[479:494] + actives[3] + \
                     mbrcode[495:510] + "\x55\xAA"
-    
+
     tmpf.file.seek(0)
     tmpf.file.truncate()
     tmpf.file.write(mbrcode)
     tmpf.file.close()
 
+    set_rw(device)
+
     logging.debug("executing: dd if='%s' of='%s' bs=512 count=1 conv=notrunc", tmpf.name, device)
     proc = subprocess.Popen(["dd", "if=%s" % tmpf.name, "of=%s" % device, "bs=512", "count=1",
                              "conv=notrunc"], stderr=file(os.devnull, "r+"))
@@ -560,6 +676,12 @@ def install_mbr(mbrtemplate, device, partition, ismirbsdmbr=True):
         raise Exception("error executing dd (third run)")
     del tmpf
 
+    # make sure we sync filesystems before returning
+    proc = subprocess.Popen(["sync"])
+    proc.wait()
+
+    set_rw(device)
+
 
 def is_writeable(device):
     """Check if the device is writeable for the current user
@@ -568,7 +690,6 @@ def is_writeable(device):
 
     if not device:
         return False
-        #raise Exception("no device for checking write permissions")
 
     if not os.path.exists(device):
         return False
@@ -588,8 +709,8 @@ def mount(source, target, mount_options):
 
     for x in file('/proc/mounts').readlines():
         if x.startswith(source):
-            raise CriticalException("Error executing mount: %s already mounted - " % source
-                                    + "please unmount before invoking grml2usb")
+            raise CriticalException("Error executing mount: %s already mounted - " % source +
+                                    "please unmount before invoking grml2usb")
 
     if os.path.isdir(source):
         logging.debug("Source %s is not a device, therefore not mounting.", source)
@@ -741,6 +862,13 @@ def get_uuid(target):
         return write_uuid(uuid_file_name)
 
 
+def get_shortname(grml_flavour):
+    """Get shortname based from grml_flavour name. The rules applied are the same as in grml-live
+    @grml_flavour: flavour name which shold be translated to shortname"""
+
+    return re.sub(r'[,._-]', '', grml_flavour)
+
+
 def copy_system_files(grml_flavour, iso_mount, target):
     """copy grml's main files (like squashfs, kernel and initrd) to a given target
 
@@ -750,9 +878,8 @@ def copy_system_files(grml_flavour, iso_mount, target):
 
     squashfs = search_file(grml_flavour + '.squashfs', iso_mount)
     if squashfs is None:
-        logging.critical("Fatal: squashfs file not found"
-        ", please check that your iso is not corrupt")
-        raise CriticalException("error locating squashfs file")
+        logging.error("error locating squashfs file")
+        raise CriticalException("squashfs file not found, please check that your iso is not corrupt")
     else:
         squashfs_target = target + '/live/' + grml_flavour + '/'
         execute(mkdir, squashfs_target)
@@ -763,24 +890,28 @@ def copy_system_files(grml_flavour, iso_mount, target):
         if filesystem_module:
             break
     if filesystem_module is None:
-        logging.critical("Fatal: filesystem.module not found")
-        raise CriticalException("error locating filesystem.module file")
+        logging.error("error locating filesystem.module file")
+        raise CriticalException("filesystem.module not found")
     else:
         exec_rsync(filesystem_module, squashfs_target + 'filesystem.module')
 
-    kernel = search_file('vmlinuz', iso_mount)
-    if kernel is None:
-        # compat for releases < 2011.12
-        kernel = search_file('linux26', iso_mount)
+    shortname = get_shortname(grml_flavour)
+    if os.path.isdir(iso_mount + '/boot/' + shortname):
+        exec_rsync(iso_mount + '/boot/' + shortname, target + '/boot')
+    else:
+        kernel = search_file('vmlinuz', iso_mount)
+        if kernel is None:
+            # compat for releases < 2011.12
+            kernel = search_file('linux26', iso_mount)
 
-    if kernel is None:
-        logging.critical("Fatal: kernel not found")
-        raise CriticalException("error locating kernel file")
+        if kernel is None:
+            logging.error("error locating kernel file")
+            raise CriticalException("Kernel not found")
 
-    source = os.path.dirname(kernel) + '/'
-    dest = target + '/' + os.path.dirname(kernel).replace(iso_mount,'') + '/'
-    execute(mkdir, dest)
-    exec_rsync(source, dest)
+        source = os.path.dirname(kernel) + '/'
+        dest = target + '/' + os.path.dirname(kernel).replace(iso_mount, '') + '/'
+        execute(mkdir, dest)
+        exec_rsync(source, dest)
 
 
 def update_grml_versions(iso_mount, target):
@@ -809,9 +940,9 @@ def update_grml_versions(iso_mount, target):
             for line in fileinput.input([target_grml_version_file], inplace=1):
                 flavour = get_flavour(line)
                 if flavour in iso_versions.keys():
-                    print iso_versions.pop(flavour)
+                    print(iso_versions.pop(flavour))
                 else:
-                    print line.strip()
+                    print(line.strip())
             fileinput.close()
 
             target_file = open(target_grml_version_file, 'a')
@@ -827,46 +958,25 @@ def update_grml_versions(iso_mount, target):
     else:
         return False
 
-def copy_grml_files(iso_mount, target):
+
+def copy_grml_files(grml_flavour, iso_mount, target):
     """copy some minor grml files to a given target
 
+    @grml_flavour: the current grml_flavour
     @iso_mount: path where a grml ISO is mounted on
     @target: path where grml's main files should be copied to"""
 
     grml_target = target + '/grml/'
     execute(mkdir, grml_target)
 
-    copy_files = [ 'grml-cheatcodes.txt', 'LICENSE.txt', 'md5sums', 'README.txt' ]
-    # handle grml-version
-    if not update_grml_versions(iso_mount, target):
-        copy_files.append('grml-version')
-
-    for myfile in copy_files:
-        grml_file = search_file(myfile, iso_mount)
-        if grml_file is None:
-            logging.warn("Warning: file %s could not be found - can not install it", myfile)
-        else:
-            exec_rsync(grml_file, grml_target + myfile)
-
-    grml_web_target = grml_target + '/web/'
-    execute(mkdir, grml_web_target)
-
-    for myfile in 'index.html', 'style.css':
-        grml_file = search_file(myfile, iso_mount)
-        if grml_file is None:
-            logging.warn("Warning: file %s could not be found - can not install it", myfile)
-        else:
-            exec_rsync(grml_file, grml_web_target + myfile)
-
-    grml_webimg_target = grml_web_target + '/images/'
-    execute(mkdir, grml_webimg_target)
-
-    for myfile in 'button.png', 'favicon.png', 'linux.jpg', 'logo.png':
-        grml_file = search_file(myfile, iso_mount)
-        if grml_file is None:
-            logging.warn("Warning: file %s could not be found - can not install it", myfile)
-        else:
-            exec_rsync(grml_file, grml_webimg_target + myfile)
+    grml_prefixe = ["GRML", "grml"]
+    for prefix in grml_prefixe:
+        filename = "{0}/{1}/{2}".format(iso_mount, prefix, grml_flavour)
+        if os.path.exists(filename):
+            exec_rsync(filename, grml_target)
+            break
+    else:
+        logging.warn("Warning: could not find flavour directory for %s ", grml_flavour)
 
 
 def handle_addon_copy(filename, dst, iso_mount, ignore_errors=False):
@@ -880,7 +990,7 @@ def handle_addon_copy(filename, dst, iso_mount, ignore_errors=False):
     file_location = search_file(filename, iso_mount)
     if file_location is None:
         if not ignore_errors:
-            logging.warn("Warning: %s not found (that's fine if you don't need it)",  filename)
+            logging.warn("Warning: %s not found (that's fine if you don't need it)", filename)
     else:
         exec_rsync(file_location, dst)
 
@@ -897,22 +1007,15 @@ def copy_addons(iso_mount, target):
     # grub all-in-one image
     handle_addon_copy('allinone.img', addons, iso_mount)
 
-    # bsd imag
+    # bsd image
     handle_addon_copy('bsd4grml', addons, iso_mount)
 
+    # DOS image
     handle_addon_copy('balder10.imz', addons, iso_mount)
 
-    # install hdt and pci.ids only when using syslinux (grub doesn't support it)
-    if options.syslinux:
-        # hdt (hardware detection tool) image
-        hdtimg = search_file('hdt.c32', iso_mount)
-        if hdtimg:
-            exec_rsync(hdtimg, addons + '/hdt.c32')
-
-        # pci.ids file
-        picids = search_file('pci.ids', iso_mount)
-        if picids:
-            exec_rsync(picids, addons + '/pci.ids')
+    # syslinux + pci.ids for hdt
+    for expr in '*.c32', 'pci.ids':
+        glob_and_copy(iso_mount + '/boot/addons/' + expr, addons)
 
     # memdisk image
     handle_addon_copy('memdisk', addons, iso_mount)
@@ -926,6 +1029,39 @@ def copy_addons(iso_mount, target):
     # ipxe.lkrn
     handle_addon_copy('ipxe.lkrn', addons, iso_mount)
 
+    # netboot.xyz
+    handle_addon_copy('netboot.xyz.lkrn', addons, iso_mount)
+
+
+def build_loopbackcfg(target):
+    """Generate GRUB's loopback.cfg based on existing config files.
+
+    @target: target directory
+    """
+
+    grub_dir = '/boot/grub/'
+    mkdir(os.path.join(target, grub_dir))
+
+    f = open(target + grub_dir + 'loopback.cfg', 'w')
+
+    f.write("# grml2usb generated grub2 configuration file\n")
+    f.write("source /boot/grub/header.cfg\n")
+
+    for defaults in glob.glob(target + os.path.sep + grub_dir + os.path.sep + "*_default.cfg"):
+        sourcefile = defaults.split(target + os.path.sep)[1]
+        logging.debug("Found source file" + sourcefile)
+        os.path.isfile(defaults) and f.write("source " + sourcefile + "\n")
+
+    for ops in glob.glob(target + os.path.sep + grub_dir + os.path.sep + "*_options.cfg"):
+        sourcefile = ops.split(target + os.path.sep)[1]
+        logging.debug("Found source file" + sourcefile)
+        os.path.isfile(ops) and f.write("source " + sourcefile + "\n")
+
+    f.write("source /boot/grub/addons.cfg\n")
+    f.write("source /boot/grub/footer.cfg\n")
+    f.close()
+
+
 def glob_and_copy(filepattern, dst):
     """Glob on specified filepattern and copy the result to dst
 
@@ -935,6 +1071,7 @@ def glob_and_copy(filepattern, dst):
     for name in glob.glob(filepattern):
         copy_if_exist(name, dst)
 
+
 def search_and_copy(filename, search_path, dst):
     """Search for the specified filename at searchpath and copy it to dst
 
@@ -945,6 +1082,7 @@ def search_and_copy(filename, search_path, dst):
     file_location = search_file(filename, search_path)
     copy_if_exist(file_location, dst)
 
+
 def copy_if_exist(filename, dst):
     """Copy filename to dst if filename is set.
 
@@ -954,6 +1092,7 @@ def copy_if_exist(filename, dst):
     if filename and (os.path.isfile(filename) or os.path.isdir(filename)):
         exec_rsync(filename, dst)
 
+
 def copy_bootloader_files(iso_mount, target, grml_flavour):
     """Copy grml's bootloader files to a given target
 
@@ -980,17 +1119,11 @@ def copy_bootloader_files(iso_mount, target, grml_flavour):
     if efi_img:
         mkdir(target + '/boot/')
         exec_rsync(efi_img, target + '/boot/efi.img')
+        handle_secure_boot(target, efi_img)
 
-    for ffile in ['f%d' % number for number in range(1, 11) ]:
+    for ffile in ['f%d' % number for number in range(1, 11)]:
         search_and_copy(ffile, iso_mount, syslinux_target + ffile)
 
-    loopback_cfg = search_file("loopback.cfg", iso_mount)
-    if loopback_cfg:
-        directory = os.path.dirname(loopback_cfg)
-        directory = directory.replace(iso_mount, "")
-        mkdir(os.path.join(target, directory))
-        exec_rsync(loopback_cfg, target + os.path.sep + directory)
-
     # avoid the "file is read only, overwrite anyway (y/n) ?" question
     # of mtools by syslinux ("mmove -D o -D O s:/ldlinux.sys $target_file")
     if os.path.isfile(syslinux_target + 'ldlinux.sys'):
@@ -1000,21 +1133,23 @@ def copy_bootloader_files(iso_mount, target, grml_flavour):
     (source_dir, defaults_file) = get_defaults_file(iso_mount, grml_flavour, "grml.cfg")
 
     if not source_dir:
-        logging.critical("Fatal: file default.cfg could not be found.")
-        logging.critical("Note:  this grml2usb version requires an ISO generated by grml-live >=0.9.24 ...")
-        logging.critical("       ... either use grml releases >=2009.10 or switch to an older grml2usb version.")
-        raise
+        raise CriticalException(
+            "file default.cfg could not be found.\n"
+            "Note:  this grml2usb version requires an ISO generated by grml-live >=0.9.24 ...\n"
+            "       ... either use grml releases >=2009.10 or switch to an older grml2usb version.")
+
+    if not os.path.exists(iso_mount + '/boot/grub/footer.cfg'):
+        logging.warning("Warning: Grml releases older than 2011.12 support only one flavour in grub.")
 
     for expr in name, 'distri.cfg', \
-        defaults_file, 'grml.png', 'hd.cfg', 'isolinux.cfg', 'isolinux.bin', \
-        'isoprompt.cfg', 'options.cfg', \
-        'prompt.cfg', 'vesamenu.cfg', 'grml.png', '*.c32':
+      defaults_file, 'grml.png', 'hd.cfg', 'isolinux.cfg', 'isolinux.bin', \
+      'isoprompt.cfg', 'options.cfg', \
+      'prompt.cfg', 'vesamenu.cfg', 'grml.png', '*.c32':
         glob_and_copy(iso_mount + source_dir + expr, syslinux_target)
 
     for filename in glob.glob1(syslinux_target, "*.c32"):
         copy_if_exist(os.path.join(SYSLINUX_LIBS, filename), syslinux_target)
 
-
     # copy the addons_*.cfg file to the new syslinux directory
     glob_and_copy(iso_mount + source_dir + 'addon*.cfg', syslinux_target)
 
@@ -1023,6 +1158,10 @@ def copy_bootloader_files(iso_mount, target, grml_flavour):
     # copy all grub files from ISO
     glob_and_copy(iso_mount + '/boot/grub/*', grub_target)
 
+    # finally (after all GRUB files have been installed) build static loopback.cfg
+    build_loopbackcfg(target)
+
+
 def install_iso_files(grml_flavour, iso_mount, device, target):
     """Copy files from ISO to given target
 
@@ -1039,8 +1178,8 @@ def install_iso_files(grml_flavour, iso_mount, device, target):
         logging.info("Copying files. This might take a while....")
         try:
             copy_system_files(grml_flavour, iso_mount, target)
-            copy_grml_files(iso_mount, target)
-        except CriticalException, error:
+            copy_grml_files(grml_flavour, iso_mount, target)
+        except CriticalException as error:
             logging.critical("Execution failed: %s", error)
             sys.exit(1)
 
@@ -1061,37 +1200,52 @@ def install_iso_files(grml_flavour, iso_mount, device, target):
     proc.wait()
 
 
+def get_device_from_partition(partition):
+    device = partition
+    partition_number = None
+    if partition[-1].isdigit() and not RE_LOOP_DEVICE.match(partition):
+        m = RE_P_PARTITION.match(partition) or RE_PARTITION.match(partition)
+        if m:
+            device = m.group(1)
+            partition_number = int(m.group(2)) - 1
+    return (device, partition_number)
+
+
 def get_flavour(flavour_str):
     """Returns the flavour of a grml version string
     """
     return re.match(r'[\w-]*', flavour_str).group()
 
+
 def identify_grml_flavour(mountpath):
     """Get name of grml flavour
 
     @mountpath: path where the grml ISO is mounted to
     @return: name of grml-flavour"""
 
-    version_file = search_file('grml-version', mountpath)
+    version_files = search_file('grml-version', mountpath, lst_return=True)
 
-    if version_file == "":
-        logging.critical("Error: could not find grml-version file.")
-        raise
+    if not version_files:
+        if mountpath.startswith("/lib/live/mount/medium"):
+            logging.critical("Error: could not find grml-version file.")
+            logging.critical("Looks like your system is running from RAM but required files are not available.")
+            logging.critical("Please either boot without toram=... or use boot option toram instead of toram=...")
+        else:
+            logging.critical("Error: could not find grml-version file.")
+        cleanup()
+        sys.exit(1)
 
     flavours = []
-    tmpfile = None
-    try:
-        tmpfile = open(version_file, 'r')
-        for line in tmpfile.readlines():
-            flavours.append(get_flavour(line))
-    except TypeError, e:
-        raise
-    except Exception, e:
-        logging.critical("Unexpected error: %s", e)
-        raise
-    finally:
-        if tmpfile:
-            tmpfile.close()
+    logging.debug("version_files = %s", version_files)
+    for version_file in version_files:
+        tmpfile = None
+        try:
+            tmpfile = open(version_file, 'r')
+            for line in tmpfile.readlines():
+                flavours.append(get_flavour(line))
+        finally:
+            if tmpfile:
+                tmpfile.close()
 
     return flavours
 
@@ -1122,6 +1276,7 @@ def handle_grub_config(grml_flavour, device, target):
     logging.debug("Updating grub configuration")
 
     grub_target = target + '/boot/grub/'
+    secureboot_target = target + '/EFI/ubuntu/'
 
     bootid_re = re.compile("bootid=[\w_-]+")
     live_media_path_re = re.compile("live-media-path=[\w_/-]+")
@@ -1135,21 +1290,24 @@ def handle_grub_config(grml_flavour, device, target):
         for regex in options.removeoption:
             remove_regexes.append(re.compile(regex))
 
-    for filename in glob.glob(grub_target + '*.cfg'):
+    shortname = get_shortname(grml_flavour)
+    for filename in glob.glob(grub_target + '*.cfg') + glob.glob(secureboot_target + '*.cfg'):
         for line in fileinput.input(filename, inplace=1):
             line = line.rstrip("\r\n")
             if option_re.search(line):
                 line = bootid_re.sub('', line)
-                line = live_media_path_re.sub('', line)
-                line = line.rstrip() + r' live-media-path=/live/%s/ bootid=%s %s ' % (grml_flavour, UUID, bootopt)
+                if shortname in filename:
+                    line = live_media_path_re.sub('', line)
+                    line = line.rstrip() + ' live-media-path=/live/%s/ ' % (grml_flavour)
+                line = line.rstrip() + r' bootid=%s %s ' % (UUID, bootopt)
                 for regex in remove_regexes:
                     line = regex.sub(' ', line)
-            print line
+            print(line)
         fileinput.close()
 
 
 def initial_syslinux_config(target):
-    """Generates intial syslinux configuration
+    """Generates initial syslinux configuration
 
     @target path of syslinux's configuration files"""
 
@@ -1166,10 +1324,11 @@ def initial_syslinux_config(target):
     data.write("include hidden.cfg\n")
     data.close()
 
+
 def add_entry_if_not_present(filename, entry):
     """Write entry into filename if entry is not already in the file
 
-    @filanme: name of the file
+    @filename: name of the file
     @entry: data to write to the file
     """
     data = open(filename, "a+")
@@ -1181,6 +1340,7 @@ def add_entry_if_not_present(filename, entry):
 
     data.close()
 
+
 def get_flavour_filename(flavour):
     """Generate a iso9960 save filename out of the specified flavour
 
@@ -1188,6 +1348,7 @@ def get_flavour_filename(flavour):
     """
     return flavour.replace('-', '_')
 
+
 def adjust_syslinux_bootoptions(src, flavour):
     """Adjust existing bootoptions of specified syslinux config to
     grml2usb specific ones, e.g. change the location of the kernel...
@@ -1226,6 +1387,7 @@ def adjust_syslinux_bootoptions(src, flavour):
         sys.stdout.write(line)
     fileinput.close()
 
+
 def adjust_labels(src, replacement):
     """Adjust the specified labels in the syslinux config file src with
     specified replacement
@@ -1254,6 +1416,7 @@ def add_syslinux_entry(filename, grml_flavour):
     data.write(generate_flavour_specific_syslinux_config(grml_flavour))
     data.close()
 
+
 def modify_filenames(grml_flavour, target, filenames):
     """Replace the standard filenames with the new ones
 
@@ -1261,7 +1424,7 @@ def modify_filenames(grml_flavour, target, filenames):
     @target: directory where the files are located
     @filenames: list of filenames to alter
     """
-    grml_filename = grml_flavour.replace('-', '_')
+    grml_filename = get_flavour_filename(grml_flavour)
     for filename in filenames:
         old_filename = "%s/%s" % (target, filename)
         new_filename = "%s/%s_%s" % (target, grml_filename, filename)
@@ -1293,10 +1456,9 @@ def handle_syslinux_config(grml_flavour, target):
     execute(mkdir, syslinux_target)
     syslinux_cfg = syslinux_target + 'syslinux.cfg'
 
-
     # install main configuration only *once*, no matter how many ISOs we have:
     syslinux_config_file = open(syslinux_cfg, 'w')
-    syslinux_config_file.write("TIMEOUT 300\n")
+    syslinux_config_file.write("timeout 300\n")
     syslinux_config_file.write("include vesamenu.cfg\n")
     syslinux_config_file.close()
 
@@ -1305,29 +1467,26 @@ def handle_syslinux_config(grml_flavour, target):
     prompt_name.close()
 
     initial_syslinux_config(syslinux_target)
-    flavour_filename = grml_flavour.replace('-', '_')
+    flavour_filename = get_flavour_filename(grml_flavour)
 
     if search_file('default.cfg', syslinux_target):
         modify_filenames(grml_flavour, syslinux_target, ['grml.cfg', 'default.cfg'])
 
     filename = search_file("new_hidden.cfg", syslinux_target)
 
-
     # process hidden file
     if not search_file("hidden.cfg", syslinux_target):
         new_hidden = syslinux_target + "hidden.cfg"
         os.rename(filename, new_hidden)
         adjust_syslinux_bootoptions(new_hidden, grml_flavour)
     else:
-        new_hidden_file =  "%s/%s_hidden.cfg" % (syslinux_target, flavour_filename)
+        new_hidden_file = "%s/%s_hidden.cfg" % (syslinux_target, flavour_filename)
         os.rename(filename, new_hidden_file)
         adjust_labels(new_hidden_file, r'\1 %s-\2' % grml_flavour)
         adjust_syslinux_bootoptions(new_hidden_file, grml_flavour)
         entry = 'include %s_hidden.cfg\n' % flavour_filename
         add_entry_if_not_present("%s/hiddens.cfg" % syslinux_target, entry)
 
-
-
     new_default = "%s_default.cfg" % (flavour_filename)
     entry = 'include %s\n' % new_default
     defaults_file = '%s/defaults.cfg' % syslinux_target
@@ -1352,6 +1511,51 @@ def handle_syslinux_config(grml_flavour, target):
     add_syslinux_entry("%s/additional.cfg" % syslinux_target, flavour_filename)
 
 
+def handle_secure_boot(target, efi_img):
+    """Provide secure boot support by extracting files from /boot/efi.img
+
+    @target: path where grml's main files should be copied to
+    @efi_img: path to the efi.img file that includes the files for secure boot
+    """
+
+    mkdir(target + '/efi/boot/')
+    efi_mountpoint = tempfile.mkdtemp(prefix="grml2usb", dir=os.path.abspath(options.tmpdir))
+    logging.debug("efi_mountpoint = %s" % efi_mountpoint)
+    register_tmpfile(efi_mountpoint)
+
+    try:
+        logging.debug("mount(%s, %s, ['-o', 'ro', '-t', 'vfat']" % (efi_img, efi_mountpoint))
+        mount(efi_img, efi_mountpoint, ['-o', 'ro', '-t', 'vfat'])
+    except CriticalException as error:
+        logging.critical("Fatal: %s", error)
+        sys.exit(1)
+
+    ubuntu_cfg = search_file('grub.cfg', efi_mountpoint + '/EFI/ubuntu')
+    logging.debug("ubuntu_cfg = %s" % ubuntu_cfg)
+    if not ubuntu_cfg:
+        logging.info("No /EFI/ubuntu/grub.cfg found inside EFI image, looks like Secure Boot support is missing.")
+    else:
+        mkdir(target + '/efi/ubuntu')
+        logging.debug("exec_rsync(%s, %s + '/efi/ubuntu/grub.cfg')" % (ubuntu_cfg, target))
+        exec_rsync(ubuntu_cfg, target + '/efi/ubuntu/grub.cfg')
+
+        logging.debug("exec_rsync(%s + '/EFI/BOOT/grubx64.efi', %s + '/efi/boot/grubx64.efi')'" % (efi_mountpoint, target))
+        exec_rsync(efi_mountpoint + '/EFI/BOOT/grubx64.efi', target + '/efi/boot/grubx64.efi')
+
+        # NOTE - we're overwriting /efi/boot/bootx64.efi from copy_bootloader_files here
+        logging.debug("exec_rsync(%s + '/EFI/BOOT/bootx64.efi', %s + '/efi/boot/bootx64.efi')'" % (efi_mountpoint, target))
+        exec_rsync(efi_mountpoint + '/EFI/BOOT/bootx64.efi', target + '/efi/boot/bootx64.efi')
+
+    try:
+        unmount(efi_mountpoint, "")
+        logging.debug('Unmounted %s' % efi_mountpoint)
+        os.rmdir(efi_mountpoint)
+        logging.debug('Removed directory %s' % efi_mountpoint)
+    except StandardError:
+        logging.critical('RuntimeError while umount %s' % efi_mountpoint)
+        sys.exit(1)
+
+
 def handle_bootloader_config(grml_flavour, device, target):
     """Main handler for generating bootloader's configuration
 
@@ -1366,7 +1570,7 @@ def handle_bootloader_config(grml_flavour, device, target):
     else:
         try:
             handle_syslinux_config(grml_flavour, target)
-        except CriticalException, error:
+        except CriticalException as error:
             logging.critical("Fatal: %s", error)
             sys.exit(1)
 
@@ -1375,12 +1579,11 @@ def handle_bootloader_config(grml_flavour, device, target):
     else:
         try:
             handle_grub_config(grml_flavour, device, target)
-        except CriticalException, error:
+        except CriticalException as error:
             logging.critical("Fatal: %s", error)
             sys.exit(1)
 
 
-
 def install(image, device):
     """Install a grml image to the specified device
 
@@ -1390,15 +1593,23 @@ def install(image, device):
     iso_mountpoint = image
     remove_image_mountpoint = False
     if os.path.isdir(image):
-        logging.info("Using %s as install base", image)
+        if options.force or os.path.exists(os.path.join(image, 'live')):
+            logging.info("Using %s as install base", image)
+        else:
+            q = raw_input("%s does not look like a Grml system. "
+                "Do you really want to use this image? y/N " % image)
+            if q.lower() == 'y':
+                logging.info("Using %s as install base", image)
+            else:
+                logging.info("Skipping install base %s", image)
     else:
         logging.info("Using ISO %s", image)
-        iso_mountpoint = tempfile.mkdtemp(prefix="grml2usb")
+        iso_mountpoint = tempfile.mkdtemp(prefix="grml2usb", dir=os.path.abspath(options.tmpdir))
         register_tmpfile(iso_mountpoint)
         remove_image_mountpoint = True
         try:
             mount(image, iso_mountpoint, ["-o", "loop,ro", "-t", "iso9660"])
-        except CriticalException, error:
+        except CriticalException as error:
             logging.critical("Fatal: %s", error)
             sys.exit(1)
 
@@ -1408,21 +1619,20 @@ def install(image, device):
         if remove_image_mountpoint:
             try:
                 remove_mountpoint(iso_mountpoint)
-            except CriticalException, error:
-                logging.critical("Fatal: %s", error)
+            except CriticalException as error:
                 cleanup()
-
+                raise
 
 
 def install_grml(mountpoint, device):
-    """Main logic for copying files of the currently running grml system.
+    """Main logic for copying files of the currently running Grml system.
 
-    @mountpoin: directory where currently running live system resides (usually /live/image)
+    @mountpoint: directory where currently running live system resides (usually /lib/live/mount/medium)
     @device: partition where the specified ISO should be installed to"""
 
     device_mountpoint = device
     if os.path.isdir(device):
-        logging.info("Specified device is not a directory, therefore not mounting.")
+        logging.info("Specified device is a directory, therefore not mounting.")
         remove_device_mountpoint = False
     else:
         device_mountpoint = tempfile.mkdtemp(prefix="grml2usb")
@@ -1430,13 +1640,13 @@ def install_grml(mountpoint, device):
         remove_device_mountpoint = True
         try:
             check_for_fat(device)
+            if not options.skipbootflag:
+                check_boot_flag(device)
+
+            set_rw(device)
             mount(device, device_mountpoint, ['-o', 'utf8,iocharset=iso8859-1'])
-        except CriticalException, error:
-            try:
-                mount(device, device_mountpoint, "")
-            except CriticalException, error:
-                logging.critical("Fatal: %s", error)
-                raise
+        except CriticalException as error:
+            mount(device, device_mountpoint, "")
     try:
         grml_flavours = identify_grml_flavour(mountpoint)
         for flavour in set(grml_flavours):
@@ -1449,8 +1659,9 @@ def install_grml(mountpoint, device):
         if remove_device_mountpoint:
             remove_mountpoint(device_mountpoint)
 
+
 def remove_mountpoint(mountpoint):
-    """remove a registred mountpoint
+    """remove a registered mountpoint
     """
 
     try:
@@ -1458,9 +1669,10 @@ def remove_mountpoint(mountpoint):
         if os.path.isdir(mountpoint):
             os.rmdir(mountpoint)
             unregister_tmpfile(mountpoint)
-    except CriticalException, error:
-        logging.critical("Fatal: %s", error)
+    except CriticalException as error:
         cleanup()
+        raise
+
 
 def handle_mbr(device):
     """Main handler for installing master boot record (MBR)
@@ -1471,12 +1683,9 @@ def handle_mbr(device):
         logging.info("Would install MBR")
         return 0
 
-    if device[-1:].isdigit():
-        mbr_device = re.match(r'(.*?)\d*$', device).group(1)
-        partition_number = int(device[-1:]) - 1
-    else:
+    mbr_device, partition_number = get_device_from_partition(device)
+    if partition_number is None:
         logging.warn("Could not detect partition number, not activating partition")
-        partition_number = None
 
     # if we get e.g. /dev/loop1 as device we don't want to put the MBR
     # into /dev/loop of course, therefore use /dev/loop1 as mbr_device
@@ -1486,16 +1695,27 @@ def handle_mbr(device):
 
     mbrcode = GRML2USB_BASE + '/mbr/mbrldr'
     if options.syslinuxmbr:
-        mbrcode = '/usr/lib/syslinux/mbr.bin'
+        mbrcode = ""
+        mbr_locations = ('/usr/lib/syslinux/mbr.bin',
+                         '/usr/lib/syslinux/bios/mbr.bin',
+                         '/usr/share/syslinux/mbr.bin')
+        for mbrpath in mbr_locations:
+            if os.path.isfile(mbrpath):
+                mbrcode = mbrpath
+                break
+
+        if mbrcode is "":
+            str_locations = " or ".join(['"%s"' % l for l in mbr_locations])
+            logging.error('Cannot find syslinux MBR, install it at %s)',
+                          str_locations)
+            raise CriticalException("syslinux MBR  can not be found at %s."
+                                    % str_locations)
     elif options.mbrmenu:
         mbrcode = GRML2USB_BASE + '/mbr/mbrldr'
 
     try:
         install_mbr(mbrcode, mbr_device, partition_number, True)
-    except IOError, error:
-        logging.critical("Execution failed: %s", error)
-        sys.exit(1)
-    except Exception, error:
+    except (IOError, Exception) as error:
         logging.critical("Execution failed: %s", error)
         sys.exit(1)
 
@@ -1513,7 +1733,7 @@ def handle_vfat(device):
             sys.exit(1)
 
         if options.force:
-            print "Forcing mkfs.fat16 on %s as requested via option --force." % device
+            print("Forcing mkfs.fat16 on %s as requested via option --force." % device)
         else:
             # make sure the user is aware of what he is doing
             f = raw_input("Are you sure you want to format the specified partition with fat16? y/N ")
@@ -1523,7 +1743,7 @@ def handle_vfat(device):
                 sys.exit(1)
         try:
             mkfs_fat16(device)
-        except CriticalException, error:
+        except CriticalException as error:
             logging.critical("Execution failed: %s", error)
             sys.exit(1)
 
@@ -1531,16 +1751,18 @@ def handle_vfat(device):
     if device is not None and not os.path.isdir(device) and options.syslinux:
         try:
             check_for_fat(device)
-        except CriticalException, error:
+        except CriticalException as error:
             logging.critical("Execution failed: %s", error)
             sys.exit(1)
 
+    if options.skipusbcheck:
+        logging.info("Not checking for removable USB device as requested via option --skip-usb-check.")
+        return
+
     if not os.path.isdir(device) and not check_for_usbdevice(device) and not options.force:
-        print "Warning: the specified device %s does not look like a removable usb device." % device
+        print("Warning: the specified device %s does not look like a removable usb device." % device)
         f = raw_input("Do you really want to continue? y/N ")
-        if f == "y" or f == "Y":
-            pass
-        else:
+        if f.lower() != "y":
             sys.exit(1)
 
 
@@ -1551,14 +1773,12 @@ def handle_compat_warning(device):
 
     # make sure we can replace old grml2usb script and warn user when using old way of life:
     if device.startswith("/mnt/external") or device.startswith("/mnt/usb") and not options.force:
-        print "Warning: the semantics of grml2usb has changed."
-        print "Instead of using grml2usb /path/to/iso %s you might" % device
-        print "want to use grml2usb /path/to/iso /dev/... instead."
-        print "Please check out the grml2usb manpage for details."
+        print("Warning: the semantics of grml2usb has changed.")
+        print("Instead of using grml2usb /path/to/iso %s you might" % device)
+        print("want to use grml2usb /path/to/iso /dev/... instead.")
+        print("Please check out the grml2usb manpage for details.")
         f = raw_input("Do you really want to continue? y/N ")
-        if f == "y" or f == "Y":
-            pass
-        else:
+        if f.lower() != "y":
             sys.exit(1)
 
 
@@ -1568,14 +1788,13 @@ def handle_logging():
     if options.verbose and options.quiet:
         parser.error("please use either verbose (--verbose) or quiet (--quiet) option")
 
+    FORMAT = "%(message)s"
     if options.verbose:
-        FORMAT = "Debug: %(asctime)-15s %(message)s"
+        FORMAT = "%(asctime)-15s %(message)s"
         logging.basicConfig(level=logging.DEBUG, format=FORMAT)
     elif options.quiet:
-        FORMAT = "Critical: %(message)s"
         logging.basicConfig(level=logging.CRITICAL, format=FORMAT)
     else:
-        FORMAT = "%(message)s"
         logging.basicConfig(level=logging.INFO, format=FORMAT)
 
 
@@ -1594,95 +1813,117 @@ def handle_bootloader(device):
 
 
 def check_options(opts):
-    """Check compability of provided user opts
+    """Check compatibility of provided user opts
 
     @opts option dict from OptionParser
     """
     if opts.grubmbr and not opts.grub:
-        logging.critical("Error: --grub-mbr requires --grub option.")
-        sys.exit(1)
+        raise CriticalException("--grub-mbr requires --grub option.")
+
+    if opts.copyonly and opts.grub:
+        raise CriticalException("Cannot use --copy-only and --grub at the same time.")
 
 
 def check_programs():
     """check if all needed programs are installed"""
     if options.grub:
-        if not which("grub-install"):
-            logging.critical("Fatal: grub-install not available (please install the "
-                             + "grub package or drop the --grub option)")
+        global GRUB_INSTALL
+        GRUB_INSTALL = which("grub-install") or which("grub2-install")
+        if not GRUB_INSTALL:
+            logging.critical("Fatal: grub-install not available (please install the " +
+                             "grub package or drop the --grub option)")
             sys.exit(1)
 
     if options.syslinux:
         if not which("syslinux"):
-            logging.critical("Fatal: syslinux not available (please install the "
-                             + "syslinux package or use the --grub option)")
+            logging.critical("Fatal: syslinux not available (please install the " +
+                             "syslinux package or use the --grub option)")
             sys.exit(1)
 
     if not which("rsync"):
         logging.critical("Fatal: rsync not available, can not continue - sorry.")
         sys.exit(1)
 
+
+def load_loop():
+    """Runs modprobe loop and throws away it's output"""
+    if not which("modprobe"):
+        logging.critical("Fatal: modprobe not available, can not continue - sorry.")
+        logging.critical("Hint: is /sbin missing in PATH?")
+        sys.exit(1)
+
+    proc = subprocess.Popen(["modprobe", "loop"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+    proc.wait()
+
+
 def main():
     """Main function [make pylint happy :)]"""
 
-    if options.version:
-        print os.path.basename(sys.argv[0]) + " " + PROG_VERSION
-        sys.exit(0)
+    try:
+        if options.version:
+            print(os.path.basename(sys.argv[0]) + " " + PROG_VERSION)
+            sys.exit(0)
+
+        if len(args) < 2:
+            parser.error("invalid usage")
 
-    if len(args) < 2:
-        parser.error("invalid usage")
+        # log handling
+        handle_logging()
 
-    # log handling
-    handle_logging()
+        # make sure we have the appropriate permissions
+        check_uid_root()
 
-    # make sure we have the appropriate permissions
-    check_uid_root()
+        check_options(options)
 
-    check_options(options)
+        load_loop()
 
-    logging.info("Executing grml2usb version %s", PROG_VERSION)
+        logging.info("Executing grml2usb version %s", PROG_VERSION)
 
-    if options.dryrun:
-        logging.info("Running in simulation mode as requested via option dry-run.")
+        if options.dryrun:
+            logging.info("Running in simulation mode as requested via option dry-run.")
 
-    check_programs()
+        check_programs()
 
-    # specified arguments
-    device = args[len(args) - 1]
-    isos = args[0:len(args) - 1]
+        # specified arguments
+        device = os.path.realpath(args[len(args) - 1])
+        isos = args[0:len(args) - 1]
 
-    if not os.path.isdir(device):
-        if device[-1:].isdigit():
-            if int(device[-1:]) > 4 or device[-2:].isdigit():
-                logging.critical("Fatal: installation on partition number >4 not supported. (BIOS won't support it.)")
-                sys.exit(1)
+        if not os.path.isdir(device):
+            if device[-1:].isdigit():
+                if int(device[-1:]) > 4 or device[-2:].isdigit():
+                    logging.warn("Warning: installing on partition number >4, booting *might* fail depending on your system.")
 
-    # provide upgrade path
-    handle_compat_warning(device)
+        # provide upgrade path
+        handle_compat_warning(device)
 
-    # check for vfat partition
-    handle_vfat(device)
+        # check for vfat partition
+        handle_vfat(device)
 
-    # main operation (like installing files)
-    for iso in isos:
-        install(iso, device)
+        # main operation (like installing files)
+        for iso in isos:
+            install(iso, device)
 
-    # install mbr
-    is_superfloppy = not device[-1:].isdigit()
-    if is_superfloppy:
-        logging.info("Detected superfloppy format - not installing MBR")
+        # install mbr
+        is_superfloppy = not device[-1:].isdigit()
+        if is_superfloppy:
+            logging.info("Detected superfloppy format - not installing MBR")
 
-    if not options.skipmbr and not os.path.isdir(device) and not is_superfloppy:
-        handle_mbr(device)
+        if not options.skipmbr and not os.path.isdir(device) and not is_superfloppy:
+            handle_mbr(device)
 
-    handle_bootloader(device)
+        handle_bootloader(device)
 
-    logging.info("Note: grml flavour %s was installed as the default booting system.", GRML_DEFAULT)
+        logging.info("Note: grml flavour %s was installed as the default booting system.", GRML_DEFAULT)
 
-    for flavour in GRML_FLAVOURS:
-        logging.info("Note: you can boot flavour %s using '%s' on the commandline.", flavour, flavour)
+        for flavour in GRML_FLAVOURS:
+            logging.info("Note: you can boot flavour %s using '%s' on the commandline.", flavour, flavour)
 
-    # finally be politely :)
-    logging.info("Finished execution of grml2usb (%s). Have fun with your grml system.", PROG_VERSION)
+        # finally be polite :)
+        logging.info("Finished execution of grml2usb (%s). Have fun with your Grml system.", PROG_VERSION)
+
+    except Exception as error:
+        logging.critical("Fatal: %s", str(error))
+        sys.exit(1)
 
 
 if __name__ == "__main__":
@@ -1692,5 +1933,5 @@ if __name__ == "__main__":
         logging.info("Received KeyboardInterrupt")
         cleanup()
 
-## END OF FILE #################################################################
+# END OF FILE ##################################################################
 # vim:foldmethod=indent expandtab ai ft=python tw=120 fileencoding=utf-8