Tested this iso with an USB stick on this machine here and it passed the tests and Anaconda started correctly.
Machine: Type: Laptop System: Hewlett-Packard product: HP G42 Notebook PC Mobo: Hewlett-Packard model: 1484 v: 77.19 BIOS: Hewlett-Packard v: F.17 date: 07/06/2010 CPU Dual core Pentium T4500 2.3GHz RAM 6GB Geraldo Simião @geraldosimiao:matrix.org Em seg, 18 de abr de 2022 14:44, Thomas Schmitt <scdbac...@gmx.net> escreveu: > Hi, > > i wrote: > > > xorrisofs option --mbr-force-bootable > > Chris Murphy wrote: > > with the bit set it means older versions of > > Tianocore or anything based on Tianocore up until maybe 6 months ago, > > won't boot. > > Is this maybe about the code snippet of Tianocore which Alexander E. > Patrakov showed in the course of the grub-bug thread of 2015/16 ? > > https://marc.info/?l=grub-bug&m=145052969801875&w=2 > " > OK, Tiano Core validates the protective partition as follows: > > // > // Verify that the Protective MBR is valid > // > for (Index = 0; Index < MAX_MBR_PARTITIONS; Index++) { > if (ProtectiveMbr->Partition[Index].BootIndicator == 0x00 && > ProtectiveMbr->Partition[Index].OSIndicator == PMBR_GPT_PARTITION > && > UNPACK_UINT32 (ProtectiveMbr->Partition[Index].StartingLBA) == 1 > ) { > break; > } > } > if (Index == MAX_MBR_PARTITIONS) { > goto Done; // i.e. not valid > } > > So here is an alternative suggestion: don't mark the protective > partition, > create another dummy MBR partition of type 0x00, mark it as bootable. > " > > That's what --mbr-force-bootable does. > The shown code will find type 0xEE == PMBR_GPT_PARTITION in partition 1 > with boot/active flag == 0x00 and be happy. > > Others which are more picky will hopefully ignore partitions of type 0x00. > UEFI 2.8 , 5.2.1 Legacy Master Boot Record (MBR) says: > "The following test must be performed to determine if a legacy MBR is > valid: > * The Signature must be 0xaa55. > * A Partition Record that contains an OSType value of zero or a > SizeInLBA value of zero may be ignored." > > For now, "may be ignored" seems to be enough of protection against trouble. > > > An alternative to --mbr-force-bootable could be to offer a 16-byte file > for download together with the instructions to patch it into a pure and > specs conformant ISO with GPT. Of course, only if a 10 year old laptop > refuses to recognize the original ISO on USB stick. > > The bytes would have to be > > { 128, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0 } > > Assumed the file is named "dummy_mbr_part2.img" the patch instruction > would be > > dd if=dummy_mbr_part2.img of=boot-grub2-f36.iso \ > conv=notrunc bs=1 seek=462 count=16 > > ------------------------------------------------------------------------- > > Ubuntu is testing this for you since about a year. :)) > > Afaik the first official ISO of this layout was > ubuntu-21.04-desktop-amd64.iso > and they did _not_ revoke it half a year later with > ubuntu-21.10-desktop-amd64.iso > > $ xorriso -indev ubuntu-21.10-desktop-amd64.iso -report_system_area plain > ... > Volume id : 'Ubuntu 21.10 amd64' > System area options: 0x00004201 > 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 > ... > > $ /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 > > ------------------------------------------------------------------------- > > Whatever, we do not yet know for sure whether the boot failure with the > Dell XPS 15 L502X is caused by the lack of a boot/active flag. > > We also don't know yet whether the failure with "CD-R and an HP Compaq > 8510w" > that was reported by Brandon Nielsen is due to drive-media problems with > the CD-R or due to problems with the ISO. > > > Have a nice day :) > > Thomas > _______________________________________________ > devel mailing list -- devel@lists.fedoraproject.org > To unsubscribe send an email to devel-le...@lists.fedoraproject.org > Fedora Code of Conduct: > https://docs.fedoraproject.org/en-US/project/code-of-conduct/ > List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines > List Archives: > https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org > Do not reply to spam on the list, report it: > https://pagure.io/fedora-infrastructure >
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