The Linux versions I have stayed with in my past, are Kanotix versions. This does not change the fact that they are Debian-based; it only means that the Kanotix Team has simplified the packaging of a specific Debian system, so that it is ready to go.
Kanotix Dragonfire -> Debian / Wheezy (obsolete),
Kanotix Spitfire -> Debian / Jessie (actual).
I have never had to do this. But if we wanted to install Linux on a UEFI-BIOS Motherboard, Kanotix makes it easy. They have a fabled installer called their ‘Acritox Installer’, which allows the user to specify an arbitrary part of the file system, which should be mounted from non-root disk partitions. Typically, this was done with the ‘
/home‘ mount-point, using a Linux-oriented file system, such as ‘
ext4‘. But for UEFI, we need to tell Acritox, to make custom, FAT32 mount-point at ‘
/boot/efi‘ , which therefore has its own partition.
The fact that this needs to be done, implies that this partition, which will either need to be a ‘Primary MBR’ or ‘Any GPT’ partition, will be readable by the BIOS, even before the O/S boots.
This is the logical place where the O/S will store the signatures, of all the Images which are supposed to be bootable. Hence, there has been no special change to the format, in which the actual ‘
initramfs‘ images are stored, but rather, every time we do an ‘
update-initramfs‘, doing so will also add an entry to this FAT32 partition, for the newly-added image.
(Edit 04/05/2016 : ) According to the fact that I have discovered a major error in my thinking, it is also a fact, that this partition does not really store EFI signatures…