X-Git-Url: https://git.grml.org/?p=grml2usb.git;a=blobdiff_plain;f=grml2usb;h=1c2ed5b1f5f6a91299a2c683e0650867a2cc3c87;hp=94f73ed058289511b980824474f1382ac3ecd5c4;hb=e4f812a475e35ce5510b5692ed69b888f80dd537;hpb=b2b4887f7616a7316f22521479a600a15668339c

diff --git a/grml2usb b/grml2usb
index 94f73ed..1c2ed5b 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
@@ -13,6 +13,7 @@ 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
@@ -41,7 +42,8 @@ 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
+GPT_HEADER = b"\x55\xaa\x45\x46\x49\x20\x50\x41\x52\x54"  # original GPT header
+GRUB_INSTALL = None
 
 RE_PARTITION = re.compile(r'([a-z/]*?)(\d+)$')
 RE_P_PARTITION = re.compile(r'(.*?\d+)p(\d+)$')
@@ -65,6 +67,7 @@ def grub_option(option, opt, value, opt_parser):
     setattr(opt_parser.values, option.dest, True)
     setattr(opt_parser.values, 'syslinux', False)
 
+
 # cmdline parsing
 USAGE = "Usage: %prog [options] <[ISO[s] | /lib/live/mount/medium]> </dev/sdX#>\n\
 \n\
@@ -101,14 +104,20 @@ 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)")
@@ -128,18 +137,22 @@ 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.
 
     @Exception: message"""
-    pass
 
 
 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
@@ -174,7 +187,7 @@ def cleanup():
         try:
             unmount(device, "")
             logging.debug('Unmounted %s' % device)
-        except RuntimeError:
+        except StandardError:
             logging.debug('RuntimeError while umount %s, ignoring' % device)
 
     for tmppath in TMPFILES.copy():
@@ -189,7 +202,7 @@ def cleanup():
                 os.unlink(tmppath)
                 logging.debug('temporary file %s deleted' % tmppath)
                 unregister_tmpfile(tmppath)
-        except RuntimeError:
+        except StandardError:
             msg = 'RuntimeError while removing temporary %s, ignoring'
             logging.debug(msg % tmppath)
 
@@ -233,7 +246,7 @@ 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
     """
@@ -242,6 +255,17 @@ 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
@@ -285,8 +309,7 @@ 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 ('', '')
@@ -335,9 +358,33 @@ def check_uid_root():
         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 as e:
+        logging.info("%s, falling back to old bootflag detection", e)
+    except ImportError as 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:]
@@ -345,12 +392,12 @@ def check_boot_flag(device):
 
         if gpt_data == GPT_HEADER:
             logging.info("GPT detected, skipping bootflag check")
-        elif bootcode[6] == '\x80':
+        elif bootcode[6] == b"\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." % boot_dev)
+                "Please enable it to be able to boot." % device)
 
 
 def mkfs_fat16(device):
@@ -456,40 +503,43 @@ 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 ...")
+                grub_device, x = get_device_from_partition(device)
+            else:
+                grub_device = device
 
-                # 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
-
-                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)
+            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=open(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)
@@ -505,6 +555,8 @@ 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)
@@ -523,14 +575,14 @@ 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)
@@ -580,7 +632,7 @@ def install_mbr(mbrtemplate, device, partition, ismirbsdmbr=True):
 
     logging.debug("executing: dd if='%s' of='%s' bs=512 count=1", device, tmpf.name)
     proc = subprocess.Popen(["dd", "if=%s" % device, "of=%s" % tmpf.name, "bs=512", "count=1"],
-                            stderr=file(os.devnull, "r+"))
+                            stderr=open(os.devnull, "r+"))
     proc.wait()
     if proc.returncode != 0:
         raise Exception("error executing dd (first run)")
@@ -588,7 +640,7 @@ def install_mbr(mbrtemplate, device, partition, ismirbsdmbr=True):
     logging.debug("executing: dd if=%s of=%s bs=%s count=1 conv=notrunc", mbrtemplate,
                   tmpf.name, nmbrbytes)
     proc = subprocess.Popen(["dd", "if=%s" % mbrtemplate, "of=%s" % tmpf.name, "bs=%s" % nmbrbytes,
-                             "count=1", "conv=notrunc"], stderr=file(os.devnull, "r+"))
+                             "count=1", "conv=notrunc"], stderr=open(os.devnull, "r+"))
     proc.wait()
     if proc.returncode != 0:
         raise Exception("error executing dd (second run)")
@@ -599,30 +651,38 @@ def install_mbr(mbrtemplate, device, partition, ismirbsdmbr=True):
 
     if partition is not None:
         if ismirbsdmbr:
-            mbrcode = mbrcode[0:439] + chr(partition) + \
-                    mbrcode[440:510] + "\x55\xAA"
+            mbrcode = mbrcode[0:439] + chr(partition).encode('latin-1') + \
+                    mbrcode[440:510] + b"\x55\xAA"
         else:
-            actives = ["\x00", "\x00", "\x00", "\x00"]
-            actives[partition] = "\x80"
+            actives = [b"\x00", b"\x00", b"\x00", b"\x00"]
+            actives[partition] = b"\x80"
             mbrcode = mbrcode[0:446] + actives[0] + \
                     mbrcode[447:462] + actives[1] + \
                     mbrcode[463:478] + actives[2] + \
                     mbrcode[479:494] + actives[3] + \
-                    mbrcode[495:510] + "\x55\xAA"
+                    mbrcode[495:510] + b"\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+"))
+                             "conv=notrunc"], stderr=open(os.devnull, "r+"))
     proc.wait()
     if proc.returncode != 0:
         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
@@ -631,7 +691,6 @@ 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
@@ -649,10 +708,10 @@ def mount(source, target, mount_options):
     # note: options.dryrun does not work here, as we have to
     # locate files and identify the grml flavour
 
-    for x in file('/proc/mounts').readlines():
+    for x in open('/proc/mounts', 'r').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)
@@ -882,9 +941,9 @@ 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')
@@ -971,6 +1030,9 @@ 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.
@@ -1058,6 +1120,7 @@ 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)]:
         search_and_copy(ffile, iso_mount, syslinux_target + ffile)
@@ -1080,9 +1143,9 @@ def copy_bootloader_files(iso_mount, target, grml_flavour):
         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"):
@@ -1096,7 +1159,7 @@ 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 been installed) build static loopback.cfg
+    # finally (after all GRUB files have been installed) build static loopback.cfg
     build_loopbackcfg(target)
 
 
@@ -1117,7 +1180,7 @@ def install_iso_files(grml_flavour, iso_mount, device, target):
         try:
             copy_system_files(grml_flavour, iso_mount, target)
             copy_grml_files(grml_flavour, iso_mount, target)
-        except CriticalException, error:
+        except CriticalException as error:
             logging.critical("Execution failed: %s", error)
             sys.exit(1)
 
@@ -1142,9 +1205,7 @@ 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)
-        if not m:
-            m = RE_PARTITION.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
@@ -1170,12 +1231,10 @@ def identify_grml_flavour(mountpath):
             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=...")
-            cleanup()
-            sys.exit(1)
         else:
             logging.critical("Error: could not find grml-version file.")
-            cleanup()
-            sys.exit(1)
+        cleanup()
+        sys.exit(1)
 
     flavours = []
     logging.debug("version_files = %s", version_files)
@@ -1185,10 +1244,6 @@ def identify_grml_flavour(mountpath):
             tmpfile = open(version_file, 'r')
             for line in tmpfile.readlines():
                 flavours.append(get_flavour(line))
-        except TypeError, e:
-            raise
-        except Exception, e:
-            raise
         finally:
             if tmpfile:
                 tmpfile.close()
@@ -1222,6 +1277,7 @@ 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_/-]+")
@@ -1236,7 +1292,7 @@ def handle_grub_config(grml_flavour, device, target):
             remove_regexes.append(re.compile(regex))
 
     shortname = get_shortname(grml_flavour)
-    for filename in glob.glob(grub_target + '*.cfg'):
+    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):
@@ -1247,12 +1303,12 @@ def handle_grub_config(grml_flavour, device, target):
                 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"""
 
@@ -1273,7 +1329,7 @@ def initial_syslinux_config(target):
 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+")
@@ -1456,6 +1512,51 @@ 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
 
@@ -1470,7 +1571,7 @@ 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)
 
@@ -1479,7 +1580,7 @@ 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)
 
@@ -1496,7 +1597,7 @@ def install(image, device):
         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. "
+            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)
@@ -1509,7 +1610,7 @@ def install(image, device):
         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)
 
@@ -1519,13 +1620,13 @@ def install(image, device):
         if remove_image_mountpoint:
             try:
                 remove_mountpoint(iso_mountpoint)
-            except CriticalException, 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.
 
     @mountpoint: directory where currently running live system resides (usually /lib/live/mount/medium)
     @device: partition where the specified ISO should be installed to"""
@@ -1540,11 +1641,12 @@ def install_grml(mountpoint, device):
         remove_device_mountpoint = True
         try:
             check_for_fat(device)
-            check_boot_flag(device)
+            if not options.skipbootflag:
+                check_boot_flag(device)
+
+            set_rw(device)
             mount(device, device_mountpoint, ['-o', 'utf8,iocharset=iso8859-1'])
-        except VerifyException, error:
-            raise
-        except CriticalException, error:
+        except CriticalException as error:
             mount(device, device_mountpoint, "")
     try:
         grml_flavours = identify_grml_flavour(mountpoint)
@@ -1568,7 +1670,7 @@ def remove_mountpoint(mountpoint):
         if os.path.isdir(mountpoint):
             os.rmdir(mountpoint)
             unregister_tmpfile(mountpoint)
-    except CriticalException, error:
+    except CriticalException as error:
         cleanup()
         raise
 
@@ -1596,6 +1698,7 @@ def handle_mbr(device):
     if options.syslinuxmbr:
         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):
@@ -1613,10 +1716,7 @@ def handle_mbr(device):
 
     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)
 
@@ -1634,7 +1734,7 @@ 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 ")
@@ -1644,7 +1744,7 @@ 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)
 
@@ -1652,16 +1752,18 @@ 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)
 
 
@@ -1672,14 +1774,12 @@ 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)
 
 
@@ -1714,26 +1814,31 @@ 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:
         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"):
@@ -1757,7 +1862,7 @@ def main():
 
     try:
         if options.version:
-            print os.path.basename(sys.argv[0]) + " " + PROG_VERSION
+            print(os.path.basename(sys.argv[0]) + " " + PROG_VERSION)
             sys.exit(0)
 
         if len(args) < 2:
@@ -1787,8 +1892,7 @@ def main():
         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)
+                    logging.warn("Warning: installing on partition number >4, booting *might* fail depending on your system.")
 
         # provide upgrade path
         handle_compat_warning(device)
@@ -1816,9 +1920,9 @@ def main():
             logging.info("Note: you can boot flavour %s using '%s' on the commandline.", flavour, flavour)
 
         # finally be polite :)
-        logging.info("Finished execution of grml2usb (%s). Have fun with your grml system.", PROG_VERSION)
+        logging.info("Finished execution of grml2usb (%s). Have fun with your Grml system.", PROG_VERSION)
 
-    except Exception, error:
+    except Exception as error:
         logging.critical("Fatal: %s", str(error))
         sys.exit(1)
 
@@ -1830,5 +1934,5 @@ 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