moving encrypted BIOS/MBR install to UEFI/GPT

[mortonP]

Dear wise forum,
I spent now quite some time, searching many places on the internet, but still fail to move an installation from BIOS/MBR to UEFI/GPT.
I would appreciate any help what is missing.

Original install:
/dev/sda1 is LUKS, LVM on top, and one LV is / (with /boot/grub)
so its an easy install from a chroot in the root LV:
grub-install --boot-directory=/boot /dev/sda
Grub loads from MBR+sda, asks for password of LUKS /dev/sda1, finds correct LV of / and there finds all the rest in /boot/grub

How to replicate this with GPT and UEFI? I failed so far :-/

GPT part1 is EF00 EFI system partition
GPT part2 is 8300 Linux, LUKS encrypted, with multiple LVs, one of them is / (with /boot/...), just like in the original setup.
So setting up from a chroot in the root LV (GPT1 mounted at /boot/efi)
grub-install --target=x86_64-efi --efi-directory=/boot/efi /dev/GPT1

this creates
/EFI/gentoo/grubx86.efi in GPT1 with a proper boot entry (checked with efibootmgr -v)
and installs all Grub modules in /boot/grub/...

Upon reboot this does not work, it stops stuck with just cursor in left upper corner

What is missing that in the UEFI install Grub also asks for the password of the LUKS encrypted GPT2 partition (containing the root LVM) to continue?
Maybe in the UEFI case something extra needs to be linked into Grub?

[sao98021]

https://superuser.com/questions/587321/ ... -partition

might have some info if you havent saw it yet

[mortonP]

Thank for the link, but this does not explain anything new.

I'll get another disk on Monday (if Amazon delivers...) and try a UEFI/MBR setup to see whether GPT is the problem.

Another observation is that Gentoo's installed Grub binary is much smaller than e.g. Ubuntu's. So maybe just some graphics or fonts are missing? I also failed to build a static Grub in Gentoo (fails with -ldevmapper linker error)

In the BIOS/MBR case the installed Grub remembers where the / LV is, without an extra config file, does anyone know whether in the UEFI/GPT case this should work the same, so the installed grubx86.efi binary has location of / LV embedded?