Secure Boot GRUB template: be more dynamic + don't overwrite with empty variable

By searching for grmlenv.cfg we can make it more dynamic
instead of having to hardcode (hd0) which might be wrong
in the grml2usb situation.

There's also no need to set root/prefix multiple times, especially
since we depend on 'root=(hd0)' for the default ISO boot anyway.

Don't overwrite prefix if the grml_orig_prefix variable is empty.

Secure Boot enabled ISOs generated with grml-live >=0.31.0 are supported
with grml2usb >=0.16.0.

diff --git a/templates/secureboot/grub.cfg b/templates/secureboot/grub.cfg
index b378aab..b5010f3 100644 (file)
--- a/templates/secureboot/grub.cfg
+++ b/templates/secureboot/grub.cfg
@@ -3,26 +3,24 @@ export grml_orig_prefix
 set grml_orig_root=$root
 export grml_orig_root
 
-set prefix=(hd0)/boot/grub/
-set root=(hd0)
-source (hd0)/boot/grub/grmlenv.cfg
-set prefix=(hd0)/boot/grub/
+search.file /boot/grub/grmlenv.cfg root
+set prefix=($root)/boot/grub/
+source ($root)/boot/grub/grmlenv.cfg
 
 if [ "$grml_secureboot" = false ] ; then
-  set root=(hd0)
   configfile /boot/grub/grub.cfg
+  # if that fails we need to fallback, but how?
 else
-  set prefix=$grml_orig_prefix
-  set root=$grml_orig_root
-
-  set timeout=20
-  set root=(hd0)
+  if [ "$grml_orig_prefix" != "" ] ; then
+    set prefix=$grml_orig_prefix
+  fi
 
   # this is basically a copy of templates/boot/grub/header.cfg but to avoid
   # failures due to Secure Boot restrictions and sourcing addons.cfg via
   # /boot/grub/loopback.cfg (and then showing entries that are at the wrong
   # position as well as don't work at all) we have to specify the appropriate
   # config here
+  set timeout=20
   if loadfont /boot/grub/ascii.pf2 ; then
     set gfxmode=auto
     insmod efi_gop