diff --git a/frontend/grub-mkrescue-sed.sh b/frontend/grub-mkrescue-sed.sh
index c6e491fa..a5488d35 100755
--- a/frontend/grub-mkrescue-sed.sh
+++ b/frontend/grub-mkrescue-sed.sh
@@ -1,6 +1,6 @@
 #!/bin/sh
 
-# Copyright (C) 2015
+# Copyright (C) 2015 - 2016
 # Thomas Schmitt <scdbackup@gmx.net>, libburnia-project.org
 # Provided under BSD license: Use, modify, and distribute as you like.
 
@@ -20,16 +20,17 @@ echo >&2
 # xorriso program. Default is the neighboring ../../xorriso/xorriso program or,
 # if that neighbor cannot be found, the system-wide installed xorriso.
 #
-# The mode "mjg" implements an experiment which should be accompanied by a
-# GNU xorriso built by
-#   export CPPFLAGS="-DLibisofs_mjg_boot_for_grub2" 
-#   ./configure && make clean && make
+# The mode "mjg" implements a layout which resembles Fedora LiveCD and Debian
+# ISOs which are bootable by ISOLINUX for BIOS and GRUB2 for EFI.
+# Its GPT is considered to be surplus, according to UEFI specs.
 #
 # The mode "mbr_only" implements an alternative layout according to UEFI 2.4,
 # section 2.5.1 and table 16. No GTP, HFS+, or APM.
 #
 # The mode "mbr_hfs" is like "mbr_only" but with HFS+ mentioned in APM.
 # It is still compliant to UEFI with no potentially deceiving GPT.
+# If you add xorrisofs option -part_like_isohybrid then no gap fillig APM
+# partition will emerge.
 #
 # These modes avoid duplicate storing of the EFI system partition "efi.img"
 # by xorrisofs option  -e "--interval:appended_partition_${partno}:all::"
@@ -175,7 +176,7 @@ then
   x=$(echo " $*" | sed \
     -e "s/-efi-boot-part --efi-boot-image/-no-pad -append_partition $partno 0xef \/tmp\/$efi_tmp_name/" \
     -e "s/--efi-boot efi\.img/-eltorito-alt-boot -e --interval:appended_partition_${partno}:all:: -no-emul-boot -isohybrid-gpt-basdat/" \
-    -e "s/--protective-msdos-label/$protective/" \
+    -e "s/--protective-msdos-label/$protective -part_like_isohybrid/" \
      )
 
 elif test x"$mode" = xmjg_copy
@@ -184,7 +185,7 @@ then
   x=$(echo " $*" | sed \
     -e "s/-efi-boot-part --efi-boot-image/-no-pad -append_partition $partno 0xef \/tmp\/$(basename "$dir")\/efi.img/" \
     -e "s/--efi-boot efi\.img/-eltorito-alt-boot -e efi.img -no-emul-boot -isohybrid-gpt-basdat/" \
-    -e "s/--protective-msdos-label/$protective/" \
+    -e "s/--protective-msdos-label/$protective -part_like_isohybrid/" \
      )
 
 elif test x"$mode" = xmbr_only
@@ -247,8 +248,18 @@ then
 fi
 
 # Run xorriso binary with the converted arguments
-"$xorriso" $MKRESCUE_SED_XORRISO_ARGS $x
-ret=$?
+use_gdb=no
+if test "$use_gdb" = yes
+then
+  gdb_file=/tmp/grub-mkrescue-sed-gdb
+  echo b assess_appended_gpt >$gdb_file
+  echo run $MKRESCUE_SED_XORRISO_ARGS $x >>$gdb_file
+  gdb -x $gdb_file "$xorriso"
+  ret=0
+else
+  "$xorriso" $MKRESCUE_SED_XORRISO_ARGS $x
+  ret=$?
+fi
 
 # Move back the ESP if it was separated
 if test -n "$efi_tmp_name" -a -e /tmp/$efi_tmp_name