I am on a system that I intend to libreboot with seagrub in the near future, I want to make my Qubes install bootable on PC-BIOS and UEFI with a GPT partition table.
I already have this figured out conceptually and tested it with other linux systems in Qemu.
- pre-partition disk with a ESP, then the rest of the disk for Qubes
- set up MBR that execubes PBR of the ESP
- set up PBR that executes pc-bios grub from ESP filesystem
- Install uefi grub and bios grub’s files into the ESP
- configure a single unified grub.cfg that chainloads grub.cfg from /boot managed by the OS
However are there any downsides or post-install experience changes I should be aware of when installing Qubes with custom paritioning like that (like steps in the update process that may not work as expected, etc.)?