Hi,
i wrote:
> Does the following bash hack "repair" the USB stick so
that it boots on
> the affected machine ?
> echo $'\x80' | dd of=/dev/sdX conv=notrunc bs=1 seek=446 count=1
Dominik 'Rathann' Mierzejewski wrote:
No, it doesn't. Still getting "Operation System not
found".
A new firmware riddle.
Does it boot with ubuntu-21.10-desktop-amd64.iso ?
(That's supposed to be pure GPT with the little extra MBR partition.)
FWIW, I can see the following messages in dmesg when inserting the
stick
into another machine:
[18881.575576] GPT:Primary header thinks Alt. header is not at the end of the disk.
[18881.575580] GPT:1334219 != 15974399
[18881.575582] GPT:Alternate GPT header not at the end of the disk.
[18881.575583] GPT:1334219 != 15974399
That has to be expected because the ISO image is smaller than the storage
device on which it was put.
(That's a reason why i promoted MBR partition table for ISOs, until the
first EFI impementations showed up which demand a smell of GPT.)
A GPT problem is unlikely to influence the first stage of BIOS booting.
[18881.575584] GPT: Use GNU Parted to correct GPT errors.
If you follow this advice then possibly the boot/active flag of the
0xEE MBR partition will be reset to 0.
(I remember that Ubuntu had a sanitizing step after booting which made
the USB stick specs compliant and thus prevented further booting of the
stick on the affected BIOS machine until the dummy partition was recreated.
https://bugs.launchpad.net/ubuntu-cdimage/+bug/1899308
especially
https://bugs.launchpad.net/ubuntu-cdimage/+bug/1899308/comments/60
)
I'll try the grub2-mkrescue ISO next.
Once made with and once without extra option
--mbr-force-bootable
please.
(We are now using a long stick to poke around in the mist.)
Have a nice day :)
Thomas