Ubuntu STR 25.10 installs but won't boot (lenovo ThinkPad T420)

[Charles M]

I wonder if grub (the boot loader) failed to install? It is strange
that the install seemed to work perfectly, but it sounds like you've
already tried most things.

Sometimes if the boot loader fails to install this bootable ISO helps:

https://sourceforge.net/projects/boot-repair-cd/files/

You would have to use something like Rufus or Unetbootin to burn it to
a USB key, then boot it an do a repair:

https://rufus.ie/en/
https://unetbootin.github.io/


On Thu, 27 Nov 2025 at 12:52, Ian Bruntlett <ian.bruntlett at gmail.com> wrote:
>
> Hi Charles,
>
> On Thu, 27 Nov 2025 at 15:38, Charles M <chaslinux at gmail.com> wrote:
>>
>> If you're installing Ubuntu it's likely that it just saw that the T420
>> is UEFI capable and installed an EFI boot partition. I would check the
>> BIOS/Startup settings and switch it to UEFI only. Since Ubuntu
>> supports secure boot it probably doesn't matter if you have secure
>> boot on or off, but if you still run into issues you could try turning
>> it off and adjusting the boot devices so Ubuntu or ATA are first.
>
>
> Apologies for the late reply.
>
> I went to BIOS -> Startup -> UEFI Legacy Boot from "BOTH" to "UEFI Only".
>
> Now Ion booting, I get the same style of menu, just with the entries:
> Ubuntu
> ATAPI CD0
> ATA HDD0
>
> after more experimentation, I now get this menu when booting:
> Ubuntu
> ATAPI CD0
> ATA HDD0
> Ubuntu
> ATAPI CD0
> ATA HDD0
>
> Any ideas?
>
> BW,
>
>
> Ian
>
>
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-- 
Charles
Mastodon: @chaslinux at techhub.social