I have two hard drives in my PC. The first one contains an ext4 partition with Debian, a swap partition and the EFI partition for Debian. The second hard drive contains Win8 and it's EFI partition.
Until now I could easily choose which OS I wanted to boot from the EFI prompt but after the last time I rebootet I can no longer boot GRUB2 and by extension Debian. I can not remember doing anything significant that could have caused this state.
The Debian partition can be mounted when booting a rescue disk and so can the EFI partition. Trying to reinstall grub on it returns a "Success" message but the newly created entry in the EFI prompt doesn't boot and throws me right back into EFI. My motherboard is an Asus Crosshair V Formula Z.
Any help is appreciated.