Support GRUB 2 BIOS + replace mbrldr/mbrmgr with syslinux MBR#104
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Support GRUB 2 BIOS + replace mbrldr/mbrmgr with syslinux MBR#104
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zeha
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zeha
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close/reopened to rerun tests |
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📦 Built packages are ready! Download here. |
Modern Grml ISOs no longer ship isolinux/syslinux files and use GRUB for both BIOS and EFI boot. Update grml2usb to handle this: - Auto-detection now prefers GRUB over syslinux (if grub-install is available) - GRUB installs directly to MBR for simpler + more reliable BIOS boot - Skip legacy mbrldr chainloader when using GRUB - Detect arm64 ISOs by flavour name and auto-switch to EFI-only mode - Gracefully fall back when syslinux files (logo.16) are missing: - To GRUB if grub-install is available - To EFI-only mode otherwise - Deprecate --grub-mbr option (GRUB now always uses MBR) Backwards compatibility: - ISOs with syslinux files still work (--bootloader=syslinux) - Explicit --bootloader= options are honored - All existing command-line options remain functional Support matrix: Host | ISO | ISO has syslinux | Result --------|-------|------------------|--------------------------- amd64 | amd64 | yes | GRUB BIOS+EFI (or syslinux if requested) amd64 | amd64 | no | GRUB BIOS+EFI amd64 | arm64 | no | EFI-only (auto-detected) arm64 | amd64 | yes/no | EFI-only (BIOS N/A on arm64 host) arm64 | arm64 | no | EFI-only See grml/grml-live#483
Recent Grml ISOs no longer ship isolinux/syslinux, as we switched to GRUB also for BIOS boot. Update grml2iso to create hybrid-bootable ISOs using GRUB for BIOS boot when isolinux is unavailable: - Detect available boot method after grml2usb populates the work directory - On arm64 hosts: prefer GRUB over isolinux (isohybrid unavailable) - Fall back to EFI-only boot with helpful warning if BIOS boot impossible - Check source ISO for GRUB boot images before attempting generation - Look for boot.img in ISO first, then system paths for hybrid MBR - Support three BIOS boot methods: 1. isolinux (if syslinux files present and not on arm64 host) 2. GRUB (using existing eltorito.img/cdboot.img from source ISO) 3. GRUB (generating eltorito.img if i386-pc modules available) Backwards compatibility: - ISOs with syslinux files work unchanged on x86 hosts - Older ISOs with isolinux still produce isolinux-based output ISOs Support matrix: Host | Source ISO | syslinux | GRUB BIOS imgs | Output ISO boots via -------|----------------|----------|----------------|---------------------- amd64 | amd64 (old) | yes | - | isolinux BIOS + EFI amd64 | amd64 (new) | no | yes | GRUB BIOS + EFI amd64 | amd64 (new) | no | no | GRUB BIOS + EFI (generated) amd64 | arm64 | no | no | EFI-only arm64 | amd64 (old) | yes | yes | GRUB BIOS + EFI (from ISO) arm64 | amd64 (old) | yes | no | EFI-only (warning) arm64 | amd64 (new) | no | yes | GRUB BIOS + EFI (from ISO) arm64 | amd64 (new) | no | no | EFI-only (warning) arm64 | arm64 | no | no | EFI-only Note: "GRUB BIOS imgs" means eltorito.img or cdboot.img + boot.img in ISO See grml/grml-live#483
xorriso is required for GRUB-based and UEFI boot support added recently, making the mkisofs/genisoimage fallback paths largely non-functional. Simplify by requiring xorriso unconditionally.
xorriso 1.1.6 is ancient (2011), so no need to check for it any longer. This also allows us to drop the check on UEFI_ENABLE, which is no longer needed.
- Remove duplicate VERSION in param loop - Remove extra closing brace in fold marker - Remove now redundant "Using xorriso" output - Remove redundant USE_GRUB=false assignment after it's no longer used - Remove unused ADD_OPTS variable - Replace $(($OPTIND - 1)) spacing with $(( OPTIND - 1 )) - Replace [ -e X -a ! -n Y ] and [ ! -z X ] with modern equivalents - Replace [ ! -n ] with [ -z ] - Replace `which` with `command -v` - Update Grml ISO name (having also new file naming schema)
The MirBSD-derived mbrldr/mbrmgr binaries offer no functional advantage over the syslinux MBR. Replace them with automatic syslinux MBR discovery (checking the same paths previously used by --syslinux-mbr), removing the need for a bundled MBR binary. Note that syslinux-common ships the mbr.bin file as /usr/lib/syslinux/mbr/mbr.bin nowadays, so added this path to our mbr_locations where to look for syslinux mbr files. FTR: - Remove mbr directory - Always use syslinux MBR when bootloader is syslinux - Remove ismirbsdmbr logic from install_mbr, always use the standard active partition flag (0x80) - Deprecate --syslinux-mbr and --mbr-menu as no-ops with warnings to preserve backwards compatibility - Drop now no longer needed dependency on nasm - Update Makefile, docs, debian/, tarball.sh + github workflow files accordingly
zeha
approved these changes
Mar 13, 2026
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📦 Built packages are ready! Download here. |
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Continuing from #98 + #99: