Hi, Pascal, I personally didn't use --removable option while install GRUB, but built a standalone EFI boot executable for grub (say, grubx64.efi with modules),it could be copied everywhere you want, and it do safe me many times.
Are these two the same thing? > My method of choice would be to install GRUB in the "removable path" > location of each EFI partition with the --removable option because it > does not need to register EFI boot entries. But I have observed an UEFI > firmware (the same which requires GPT for EFI boot) which ignores the > removable path location if an EFI boot entry pointing to the same disk > exists (even though not functional) so beware. Actually the most > difficult part is to work around the UEFI firmware bugs. -- Liu An