Booting loopmounted isos in EFI grub

I have a usb stick with grub installed that can loopmount live disc isos so I don't have to repartition to change my available live discs. A typical entry looks like this:
This works fine and lets me drop any number of isos in there, write up a config, and just boot from it at will.

Recently I've bought a new USB stick and used GPT to ensure it can boot in both MBR and EFI mode. Both of these modes boot grub and the EFI config correctly redirects to the MBR config like so:
The problem is that while EFI grub boots and uses the configs I want the actual live discs refuse to boot - I thought it might be that they aren't signed but then I read something about grub's linuxefi/initrdefi commands, but they don't seem to exist in the grub documentation.

Anyone know how to do what I'm talking about here, or what could be causing them not to boot?

Statistics: Posted by J V — 2024-07-10 08:25 — Replies 3 — Views 55

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