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mkarchiso: use -isohybrid-gpt-basdat instead of -appended_part_as_gpt for ISOs that will support BIOS booting

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Some hardware, like Lenovo Thinkpad T420, will not BIOS boot if the disk has a valid GPT.
See https://bbs.archlinux.org/viewtopic.php?id=264096 .

Instead of a valid GPT, change to a valid MBR and invalid GPT similar to what was used before 729d16b48c. That layout, despite having crazy partition tables, boots everywhere.
The difference is that -append_partition is still kept and specified before -isohybrid-gpt-basdat. Thus the appended partition will be listed as EFI system partition in MBR and as Microsoft basic partition in the invalid GPT.

Fixes #102.
This commit is contained in:
nl6720 2021-03-06 09:59:22 +02:00
parent c8599788f0
commit 09b6127fe8
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GPG Key ID: 5CE88535E188D369
1 changed files with 31 additions and 13 deletions
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@ -681,15 +681,10 @@ _add_xorrisofs_options_bios.syslinux.mbr() {
'-isohybrid-mbr' "${isofs_dir}/syslinux/isohdpfx.bin"
# When GPT is used, create an additional partition in the MBR (besides 0xEE) for sectors 0–1 (MBR
# bootstrap code area) and mark it as bootable
# This violates the UEFI specification, but may allow booting on some systems
# May allow booting on some systems
# https://wiki.archlinux.org/index.php/Partitioning#Tricking_old_BIOS_into_booting_from_GPT
'--mbr-force-bootable'
# Set the ISO 9660 partition's type to "Linux filesystem data"
# When only MBR is present, the partition type ID will be 0x83 "Linux" as xorriso translates all
# GPT partition type GUIDs except for the ESP GUID to MBR type ID 0x83
'-iso_mbr_part_type' '0FC63DAF-8483-4772-8E79-3D69D8477DE4'
# Move the first partition away from the start of the ISO to match the expectations of partition
# editors
# Move the first partition away from the start of the ISO to match the expectations of partition editors
# May allow booting on some systems
# https://dev.lovelyhq.com/libburnia/libisoburn/src/branch/master/doc/partition_offset.wiki
'-partition_offset' '16'
@ -702,12 +697,26 @@ _add_xorrisofs_options_uefi-x64.systemd-boot.esp() {
# partition will not be mountable
# shellcheck disable=SC2076
[[ " ${xorrisofs_options[*]} " =~ ' -partition_offset ' ]] || xorrisofs_options+=('-partition_offset' '16')
xorrisofs_options+=(
# Attach efiboot.img as a second partition and set its partition type to "EFI system partition"
'-append_partition' '2' 'C12A7328-F81F-11D2-BA4B-00A0C93EC93B' "${work_dir}/efiboot.img"
# Ensure GPT is used as some systems do not support UEFI booting without it
'-appended_part_as_gpt'
)
# Attach efiboot.img as a second partition and set its partition type to "EFI system partition"
xorrisofs_options+=('-append_partition' '2' 'C12A7328-F81F-11D2-BA4B-00A0C93EC93B' "${work_dir}/efiboot.img")
# Ensure GPT is used as some systems do not support UEFI booting without it
# shellcheck disable=SC2076
if [[ " ${bootmodes[*]} " =~ ' bios.syslinux.mbr ' ]]; then
# A valid GPT prevents BIOS booting on some systems, instead use an invalid GPT (without a protective MBR).
# The attached partition will have the EFI system partition type code in MBR, but in the invalid GPT it will
# have a Microsoft basic partition type code.
if [[ ! " ${bootmodes[*]} " =~ ' uefi-x64.systemd-boot.eltorito ' ]]; then
# If '-isohybrid-gpt-basdat' is specified before '-e', then the appended EFI system partition will have the
# EFI system partition type ID/GUID in both MBR and GPT. If '-isohybrid-gpt-basdat' is specified after '-e',
# the appended EFI system partition will have the Microsoft basic data type GUID in GPT.
if [[ ! " ${xorrisofs_options[*]} " =~ ' -isohybrid-gpt-basdat ' ]]; then
xorrisofs_options+=('-isohybrid-gpt-basdat')
fi
fi
else
# Use valid GPT if BIOS booting support will not be required
xorrisofs_options+=('-appended_part_as_gpt')
fi
}
# systemd-boot via El Torito
@ -723,6 +732,15 @@ _add_xorrisofs_options_uefi-x64.systemd-boot.eltorito() {
# Boot image is not emulating floppy or hard disk; required for all known boot loaders
'-no-emul-boot'
)
# A valid GPT prevents BIOS booting on some systems, use an invalid GPT instead.
if [[ " ${bootmodes[*]} " =~ ' bios.syslinux.mbr ' ]]; then
# If '-isohybrid-gpt-basdat' is specified before '-e', then the appended EFI system partition will have the
# EFI system partition type ID/GUID in both MBR and GPT. If '-isohybrid-gpt-basdat' is specified after '-e',
# the appended EFI system partition will have the Microsoft basic data type GUID in GPT.
if [[ ! " ${xorrisofs_options[*]} " =~ ' -isohybrid-gpt-basdat ' ]]; then
xorrisofs_options+=('-isohybrid-gpt-basdat')
fi
fi
else
# The ISO will not contain a GPT partition table, so to be able to reference efiboot.img, place it as a
# file inside the ISO 9660 file system