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grub-mkrescue-sed.sh: MKRESCUE_SED_IN_EFI_NO_PT="extra" to erase MBR signature

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Thomas Schmitt 2019-04-22 20:38:37 +02:00
parent 95c2e7cbda
commit 1eb51f44da
1 changed files with 10 additions and 2 deletions
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12
frontend/grub-mkrescue-sed.sh
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@ -120,6 +120,7 @@ fi
# "yes" overwrites the MBR partition table area in the EFI boot image by zeros.
# Some EFI implementations get stuck when seeing in the EFI partition a
# partition table entry which begins at LBA 0.
# "extra" not only zeros the partition table but also the MBR signature.
efi_zero_inner_pt=no
if test -n "$MKRESCUE_SED_IN_EFI_NO_PT"
then
@ -192,24 +193,31 @@ then
find "$dir"
fi
if test "$efi_zero_inner_pt" = yes
if test "$efi_zero_inner_pt" = yes -o "$efi_zero_inner_pt" = extra
then
did_dd=0
if test -e "$dir"/efi.img
then
# Look for 0x55 0xAA in bytes 510 and 511
magic=$(dd bs=1 skip=510 count=2 if="$dir"/efi.img 2>/dev/null | \
od -c | head -1 | awk '{print $2 " " $3}')
if test "$magic" = "U 252"
then
echo "Performing actions for MKRESCUE_SED_IN_EFI_NO_PT=$efi_zero_inner_pt" >&2
dd if=/dev/zero bs=1 seek=446 count=64 conv=notrunc of="$dir"/efi.img
did_dd=1
if test "$efi_zero_inner_pt" = extra
then
dd if=/dev/zero bs=1 seek=510 count=2 conv=notrunc of="$dir"/efi.img
fi
echo >&2
fi
fi
if test "$did_dd" = 0
then
echo >&2
echo "$0 : NOTE : No EFI image found or no MBR signature in it." >&2
echo "$0 : NOTE : Will not obey MKRESCUE_SED_IN_EFI_NO_PT=yes" >&2
echo "$0 : NOTE : Will not obey MKRESCUE_SED_IN_EFI_NO_PT=$efi_zero_inner_pt" >&2
echo >&2
fi
fi