On Sun, Oct 24, 2021 at 09:09:46AM +0200, Thomas Schmitt wrote: > Hi, > > > there a better source to report suggestions for mac builds? (intel x86) > > The debian-cd mailing list is in charge of the installation ISOs. > https://lists.debian.org/debian-cd/ > There is also the debian-live mailing list which is in charge of the > Debian Live ISOs. > https://lists.debian.org/debian-live/
Debian CD/DVD team is now the Images team- https://wiki.debian.org/Teams/DebianCd [I hang around with them and test releases] Notably, we do _not_ prepare / maintain the debian-live images which are made by the debian-live team, although all images are tested when we make a point release or new major release. > > > > i found out that the debian installer is able to boot in UEFI-mode if I > > replace the DOSMBR with a GPT header within the usb installer media. > > Ubuntu changed to a GPT layout: > > $ /sbin/fdisk -l ubuntu-21.10-desktop-amd64.iso > Disk ubuntu-21.10-desktop-amd64.iso: 2.9 GiB, 3116482560 bytes, 6086880 > sectors > Units: sectors of 1 * 512 = 512 bytes > Sector size (logical/physical): 512 bytes / 512 bytes > I/O size (minimum/optimal): 512 bytes / 512 bytes > Disklabel type: gpt > Disk identifier: EF83665C-2F29-48D6-8C3F-80F5A69CFEB7 > > Device Start End Sectors Size Type > ubuntu-21.10-desktop-amd64.iso1 64 6077751 6077688 2.9G Microsoft > basic da > ubuntu-21.10-desktop-amd64.iso2 6077752 6086215 8464 4.1M EFI System > ubuntu-21.10-desktop-amd64.iso3 6086216 6086815 600 300K Microsoft > basic da > > $ xorriso -indev ubuntu-21.10-desktop-amd64.iso -report_system_area plain > ... > System area summary: MBR protective-msdos-label grub2-mbr cyl-align-off GPT > ISO image size/512 : 6086880 > Partition offset : 16 > MBR heads per cyl : 0 > MBR secs per head : 0 > MBR partition table: N Status Type Start Blocks > MBR partition : 1 0x00 0xee 1 6086879 > MBR partition : 2 0x80 0x00 0 1 > GPT : N Info > GPT disk GUID : 5c6683ef292fd6488c3f80f5a69cfeb7 > GPT entry array : 2 248 separated > GPT lba range : 64 6086816 6086879 > GPT partition name : 1 490053004f003900360036003000 > GPT partname local : 1 ISO9660 > GPT partition GUID : 1 5c6683ef292fd6488c3e80f5a69cfeb7 > GPT type GUID : 1 a2a0d0ebe5b9334487c068b6b72699c7 > GPT partition flags: 1 0x1000000000000001 > GPT start and size : 1 64 6077688 > GPT partition name : 2 41007000700065006e006400650064003200 > GPT partname local : 2 Appended2 > GPT partition GUID : 2 5c6683ef292fd6488c3d80f5a69cfeb7 > GPT type GUID : 2 28732ac11ff8d211ba4b00a0c93ec93b > GPT partition flags: 2 0x0000000000000000 > GPT start and size : 2 6077752 8464 > GPT partition name : 3 4700610070003100 > GPT partname local : 3 Gap1 > GPT partition GUID : 3 5c6683ef292fd6488c3c80f5a69cfeb7 > GPT type GUID : 3 a2a0d0ebe5b9334487c068b6b72699c7 > GPT partition flags: 3 0x1000000000000001 > GPT start and size : 3 6086216 600 > > > > I'm wondering who I can send this suggestion to, as there are mac users who > > are resorting to the more dangerous hybrid dosmbr+GPT configuration. > > Actually only the MBR is valid in Debian ISOs, whereas their GPT is not. > > It may be that the GPT debris was initially cruft from Matthew Garrett's > development of BIOS+EFI ISOs in 2012 (for Fedora). > Nevertheless this invalid GPT data lure some EFI implementations into > booting, which would not boot otherwise. So it is not totally useless. > > On the other hand there are some legacy BIOS implementations which do no > consider a USB stick for booting if there is no "boot" flag at some > MBR partition. But such a flag is not allowed with the Protective MBR > partition of type 0xee, which announces the presence of the GPT. > Ubuntu currently adds a dummy MBR partition with type 0, which carries > the boot flag but is currently ignored by the EFI implementations. > (No warranty that this will stay so in future.) > > > > there's a mac iso on the debian servers, but I am not sure how I can > > determine who is in charge of maintaining it. > The Mac iso on the Debian servers is for a specific model of early Intel Macs from about 2007/2008 which had an interesting EFI configuration such that nothing else would boot on it. There have been other threads on this in debian-user and certainly debian-cd in the last year or so. In general, the amd64 netinst or amd64 DVD1 is absolutely fine: I'm unsure what firmware the Mac requires but if firmware is a problem, then there is an unofficial image with non-free firmware included [prepared by the same team - unofficial because non-free is not a part of Debian and we can't always distribute source/repackage/fix packages we're given and are reliant on third parties not because the quality is any worse] https://cdimage.debian.org/cdimage/unofficial/non-free/cd-including-firmware/11.1.0+nonfree/amd64/iso-cd/firmware-11.1.0-amd64-netinst.iso > It gets produced by debian-cd. > (I think its name is misleading, as it is a BIOS-only image without EFI > boot lures. Motivated by some Macs, but containing no specific extras > for Macs.) > > > Have a nice day :) > > Thomas > Hope this helps. With every good wish, as ever, Andy Cater
