So I have a problem I cannot figure out. I've been trying different distro's on my Lenovo T15 Gen2. Tried Ubuntu, Ubuntu Web and last Pop!_OS in the past days. However, since installing Pop!_OS, I am no longer able to boot from USB. When I choose boot from USB in the Bios, the screen goes to GNU Grub version 2.04.

I've looked for solutions online and found two:
1. I tried to follow this user's advice, to switch "OS Mode Selection" in the Boot menu from "UEFI OS" to "CSM and UEFI OS", which appears to solve the problem. But because I am on a THinkpad T15 gen2, CMS is no longer supported, so this is not an option for me.
2. There is one other answer that I found online here, but it is too technical for me. I do not understand it.

I am fairly sure the problem lies with the PopOS install, bc others seem to have the same problem, but mainly because I am working with 2 USBs for the Linux installs, and one of them is still exactly the same as the one I used yesterday to install Ubuntu Web. Yesterday it worked fine, now - goes to Grub. The only thing that has changed in the meantime is the PopOS install (from the 2nd USB).

Does anyone have any suggestions for how to fix this?
thanks,
Rik

For anyone with the same problem, the solution is posted here: https://www.reddit.com/r/pop_os/comm...omment/jej8qj4
Basically, the solution is to use Ventoy https://www.ventoy.net/ as a tool for getting the USB boot-ready, then it boots from USB as normal

I'm not clear on what you mean by that, installing? Do you mean you wrote the Pop OS iso to the USB and can no longer boot the USB or did you install Pop OS to the computer and now have problems booting? One frequent problem is that no all USB port can be used to boot. Did you use the same port on the multiple attempts?

You indicate you have no BIOS firmware option to boot Legacy/CSM. That is becoming the default on many newer computers. I have the same on a laptop I purchased in 2020. I'm not sure what the difference is in Ventoy, I've never used it myself. I generally install Grub to the USB to boot both Legacy and UEFI and then manually create menuentries in Grub. If Ventoy worked easily for you it is good that you posted as it should help many new users.

Thanks @yancek for the reply. I meant that I installed PopOS on my PC and afterwards I could no longer install a new OS, they locked me in . All my USBs with iso files burnt to them with Balena Etcher would no longer load when I selected "boot from USB" in the UEFI, the PC went to GNU Grub then instead of booting the USB. But when I 'burned' the isos with Ventoy it did work!
Rik