This weekend, I got my hands on a (really) cheap iMac 27" from 2013 with i5 and 32G of ram so what better use for it than to install OpenSUSE on it.
This is a pretty painless experience, just like a regular PC, which it for all intends and purposes, really is. However, after installing I noticed that it didn’t boot. I could boot from disk using the USB installer thumbdrive, but not with it removed from the system.
After a bit of investigating, it became clear that the installer had not installed the necessary boot files in EFI and instead installed grub in MBR. Given that intel Macs do not support booting from MBR, it wasn’t surprising to see it not being able to boot.
So I reinstalled again, but in summary I went into the boot options and changed grub to grub2-efi manually and proceeded while ignoring the warning that what I was telling it to do was installing an incompatible boot configuration and the system might not be able to start.
After ignoring all the warnings, the installation proceeded as normal followed by a reboot. This time, the machine booted into OpenSUSE as expected.
I have installed Linux on different Mac hardware before with other distributions, and all of them correctly installed using grub2-efi by default. However, for some reason OpenSUSE does not and unless you know you actually need EFI to boot on one of these, you’re more than likely being stumped by a system that refuses to boot. This must be a bug in the EFI detection?