So, in the past, I used to make a bit of money fixing up comps for folks.
With slightly trickier cases, I used to boot up puppy Linux to check the more essential hardwares (and if it booted, back up essential files for the customer). My students are now asking how to manage similar things.
Alas, puppy is no good for a modern system, as it really does not like UEFI boot. I was wondering if anyone can recommend an alternative.
I'm looking for a very lightweight gui os I that can run some hardware diagnostic tools, runs on a wide range of hardware, that is easy enough to set up on a pen for novice users.
I'm a fan of SystemRescue. It's specifically designed for backing up and fixing disk layouts, and it supports both BIOS and UEFI booting.
I've never tried it on Secure Boot enabled devices (I usually disable secureboot before troubleshooting systems), so I do not know if they use a valid signed efi-stub.
For "simple" stuff, I usually boot a live ubuntu image. If the machine has sufficient RAM, I can get away with installing quite a few packages that I need for troubleshooting (gparted, gdisk, etc.).
I'd recommend getting a 32 or 64gb stick and put Ventoy on it. Then drop whatever distros you fancy on there and try them out. Ventoy is uefi compatible.