Hi, Andrew M.A. Cater wrote: > > for an *old* Intel-based Mac Mini that had issues with > > image booting from certain disk layouts. > > https://wiki.debian.org/MacMiniIntel#Macmini_2.2C1
I think the paragraph before that one explains better what's the problem with old Macs and EFI-ready Debian ISOs. https://wiki.debian.org/MacMiniIntel#Macmini_1.2C1 "When booting off CD/DVD, if there is more than one El Torito boot record on the disc then the firmware gets confused. It tried to offer a choice of the boot options, but it locks up instead." So it is the second El Torito boot catalog entry for the EFI boot image (System Partition) which causes the problems. I would expect that the problem only occurs when the ISO is presented on an optical medium. But firmwares are not very affine to specs. So one would have to test whether booting a normal amd64 ISO from USB stick works on the affected Macs. Roland Clobus wrote: > If the netinst and live images are able to properly detect the hardware they > are running on (including firmware bugs etc), I think it would be nice to > remove the mac-specific images. At the stage when the problem occurs, the netinst ISO has no own brain involved. Only the firmware is running and stumbles over the still passive El Torito boot catalog. What we could offer is a program which looks up the address of the boot catalog from the boot record (2048-byte-block 17, offset 71 bytes, 32 bit little-endian) and then zeroizes in the boot catalog block all bytes after offset 64. This would remove the boot catalog entry for EFI and make a normal amd64 netinst look like the "mac" amd64 netinst. With 12.7.0: $ cp debian-12.7.0-amd64-netinst.iso test.iso $ xorriso -indev test.iso -report_el_torito plain ... El Torito catalog : 1130 1 El Torito cat path : /isolinux/boot.cat El Torito images : N Pltf B Emul Ld_seg Hdpt Ldsiz LBA El Torito boot img : 1 BIOS y none 0x0000 0x00 4 5891 El Torito boot img : 2 UEFI y none 0x0000 0x00 19040 1131 El Torito img path : 1 /isolinux/isolinux.bin El Torito img opts : 1 boot-info-table isohybrid-suitable El Torito img path : 2 /boot/grub/efi.img $ expr 1130 '*' 2048 + 64 2314304 $ dd if=/dev/zero conv=notrunc of=test.iso bs=1 seek=2314304 count=1984 $ xorriso -indev test.iso -report_el_torito plain ... El Torito catalog : 1130 1 El Torito cat path : /isolinux/boot.cat El Torito images : N Pltf B Emul Ld_seg Hdpt Ldsiz LBA El Torito boot img : 1 BIOS y none 0x0000 0x00 4 5891 El Torito img path : 1 /isolinux/isolinux.bin El Torito img opts : 1 boot-info-table isohybrid-suitable Now there is only one boot image and the Mac firmware has no reason to ask the user for choice. EFI firmware is supposed to not boot any more from optical medium but to still boot from USB stick (because the partition table still points to the system partition). Have a nice day :) Thomas
