GRUB has a wrong $cmdpath when booted from an optical disc
I was testing archlinux-2022.06.21-x86_64.iso and when booting it from an "optical disc" (an emulated one using IODD 2531) on my laptop (HP ProBook 450 G2), GRUB didn't load $cmdpath/grub.cfg and dumped me in the shell.
echo $cmdpath returned (cd0)/EFI/Boot. Notice that it's Boot not BOOT, but ls (cd0)/EFI/ showed that the directory is indeed called BOOT.
Manually running configfile (cd0)/EFI/BOOT/grub.cfg worked fine and loaded the menu.