On 06/07/17 10:23, Alexander Graf wrote: Hi,
> On 07/06/2017 11:14 AM, Andre Przywara wrote: >> The UEFI spec allows an EFI system partition (ESP, with the bootloader or >> kernel EFI apps on it) to reside on a disk using a "legacy" MBR >> partitioning scheme. >> But in contrast to actual legacy disks the ESP is not marked as >> "bootable" using bit 7 in byte 0 of the legacy partition entry, but is >> instead using partition *type* 0xef (in contrast to 0x0b or 0x0c for a >> normal FAT partition). The EFI spec isn't 100% clear on this, but it even >> seems to discourage the use of the bootable flag for ESPs. >> Also it seems that some EFI implementations (EDK2?) even seem to ignore >> partitions marked as bootable (probably since they believe they contain >> legacy boot code). >> The Debian installer [1] (*not* mini.iso), for instance, contains such an >> MBR, where none of the two partitions are marked bootable, but the ESP >> has clearly type 0xef. >> Now U-Boot cannot find the ESP on such a disk (USB flash drive) and >> fails to load the EFI grub and thus the installer. >> >> Since it all boils down to the distro bootcmds eventually calling >> "part list -bootable" to find potential boot partitions, it seems logical >> to just add this "partition type is 0xef" condition to the is_bootable() >> implementation. >> >> This allows the bog standard arm64 Debian-testing installer to boot from >> an USB pen drive on Allwinner A64 boards (Pine64, BananaPi-M64). >> (Ubuntu and other distribution installers don't have a legacy MBR, so >> U-Boot falls back to El Torito there). >> >> [1] >> https://cdimage.debian.org/cdimage/daily-builds/daily/arch-latest/arm64/iso-cd/ >> >> Signed-off-by: Andre Przywara <andre.przyw...@arm.com> > > I think this change is perfectly reasonable, yes. > > Reviewed-by: Alexander Graf <ag...@suse.de> so browsing through the whole thread again my understanding is that the concerns have been cleared. So are there any objections to this patch? Who would be the person I should send this to? Cheers Andre. > > > Alex > >> --- >> disk/part_dos.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/disk/part_dos.c b/disk/part_dos.c >> index 7ede15e..7aff73d 100644 >> --- a/disk/part_dos.c >> +++ b/disk/part_dos.c >> @@ -44,7 +44,7 @@ static inline int is_extended(int part_type) >> static inline int is_bootable(dos_partition_t *p) >> { >> - return p->boot_ind == 0x80; >> + return (p->sys_ind == 0xef) || (p->boot_ind == 0x80); >> } >> static void print_one_part(dos_partition_t *p, lbaint_t >> ext_part_sector, > > > _______________________________________________ > U-Boot mailing list > U-Boot@lists.denx.de > https://lists.denx.de/listinfo/u-boot _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot
