invalid arch-independant ELF magic

[geole0]

Hello
I decide to install the DAILY version of Hirsute Hippo using a "legacy only" computer.
I choose to install on the whole disk. As a result:
The msdos partition table is destroyed and replaced with a GPT partition table.
A 32 MiB bios_grub partition is created,
A 512 MiB EFI partition is created
And another partition with the rest of the available disk space is created.

But the boot is impossible with this error message
ERROR: Invalid arch-independent ELF magic
Entering rescue mode ...

In this mode, typing the characters "help" "boot" "vmlinux" etc ... gives the response 'unknown command "
Only the set command responds correctly and shows that the variables are correctly positioned..
( boot=(hd0,gpt3)/boot/grub )

The workaround found to boot the shaggy version is as follows

1) Boot from another disk and use another ubuntu, make it discover all the O.S. present. (sudo update-grub) then reboot and choose version 21.04 from the list.
that works properly.

But this solution does not suit me. But it shows that the problem is probably with the contents of the bios_grub partition which I cannot read.

Please quickly improve the grub.

See also this french discussion : https://forum.ubuntu-fr.org/viewtopic.php?id=2060928

Have a nice week end

[Dimitri John Ledkov (xnox)]

using a "legacy only" computer => can you please describe a little bit more as to what this machine is?

Make / model / specs / etc?

[geole0 (geole0)]

Hello
This "legacy only" computer is old. It now contains an SSD disk composed of four partitions including windows 10 and ubuntu 20.04.
Another disk containing windows XP and windows 7.
A third larger disc containing the duplications of the two preceding discs.

I know the ubuntu boots fairly well since I participate in an important way in the EFI part with another computer in the following documentations,
https://doc.ubuntu-fr.org/refind
https://doc.ubuntu-fr.org/tutoriel/installation_sur_disque_usb

I noticed that the installation of ubuntu has changed a lot with version 20.04.
So I want to see how version 21.04 will behave.

So I decided to use this 64-bit computer which only knows the LEGACY mode to install the future version 21.04 on an external hard drive by choosing to overwrite the entire drive.
(I often used the option something else.)
 The installer therefore overwrote the ms-dos partition table to install a GPT partition table.

Everything is going well. The boot is done well with this external drive. But I get the quoted message which is the subject of my correction request.

I don't quite know how to understand it. I saw that it was cited a lot several years ago and that it seemed to be a mix between 32 bit mods and 64 bit mods.

Subsequently I have the following tests:

Boot the ubuntu from the SSD (20.04.1). Make him discover the O.S. Installed. He forgets to look at the contents of the external disks !!!
So I duplicated by gparted the root partition 21.01 in the big disk and restarted the detection. At the next boot, I can choose version 21.04 (the duplication of the external disk in the large 3 TB disk formatted GPT). It works. I even updated it yesterday.

I also plugged the external drive into my laptop which is in efi.
The boot works perfectly well!

It is possible that installing version 20.04 or version 20.10 will give the same result. I did not try.

Hope this can be of help to you.

[geole0 (geole0)]

Hello
Today I downloaded the new DAILY version again
I see the same problem again!

[geole0 (geole0)]

So under grub rescue, with four commands lines

set root=(hd0,gpt3)
set prefix=(hd0,gpt3)/usr/lib/grub
insmod nornal
normal

then under grub, with three commands lines
linux /boot/vmlinuz root=/dev/sdd3 ro
initrd /boot/initrd.img
boot

This troubleshooting works but it is not normal to have to use it!