Comment 7 for bug 1878541

With unpacked kernel.efi boot to rdinit=/bin/sh res usage is 456756

so it feels as if (loop) device is not freed by grub / shim / firmware.

Next up is to try to play with things interactively in grub shell, to try to figure out which commands cause memory to baloon.

Or like see if it can be freed after loading things from squashfs.

UC18 loads kernels from squashfs in under 512MB => compare if grub in uc18 is better.