I have installed Fedora 40 Silverblue on a USB to have a system that I could use between multiple devices from a USB that is separate from the system installed on the hard drive.
I installed in legacy boot mode. The installer installed with GPT partitioning (as is normal for a few releases now even with legacy boot).
The issue is that for some reason this specific USB install doesn’t boot on a specific laptop (others do, for example, the installer) and boots just fine on other laptops.
I completed the installation on my HP Omen gaming laptop (I didn’t install any Nvidia drivers, used nouveau). I can boot it just fine from the boot menu in legacy mode.
However, when I try to boot it on my Thinkpad X270 it simply doesn’t work. I have tried various settings in the setup utiity, USB boot is enabled, legacy boot is enabled (in fact, the install on the hard drive is in legacy boot mode), I tried disabling TPM and also allowing UEFI. If I move the USB over the hard drive in the boot priority it is simply skipped. If I try to boot it through the boot menu, the screen goes blank for half a second and the boot menu returns. No loading GRUB message is shown. I tried holding shift, pressing escape to show the GRUB menu but it doesn’t work. Note that the installer USB boots just fine, and it is also GPT partitioned and I boot it in legacy mode.
And this isn’t a case of it working only on the laptop I did the installation on. The USB boots justs fine on my Dell XPS m1330 too (only supports legacy mode).
I would prefer to not reinstall as I spent a somewhat significant amount of time setting everything up.
How to fix this? Why is this specific install not even loading GRUB on this specific laptop?