I had trouble getting Linux to boot properly on a ThinkStation S30.
The BIOS appears to behave in a similar way to what is described above, only I'd suggest that the Lenovo code just checks for the presence of (at least) "Windows Boot Manager" in the UEFI firmware. It does not seem to force it to load. The Lenovo UEFI implementation in the BIOS for this machine will happily obey the specified BootOrder and load entries that are not labelled "Windows Boot Manager" or "Red Hat Enterprise Linux".
Although the implementation is definitely silly, this might alleviate some of the concerns about having to have an entry "Windows Boot Manager" or "Red Hat Enterprise Linux" that actually points to a GRUB2 loader for another distribution.
I've provided a full description of my findings over on the Lenovo community forums. I'm posting here because this is probably the first article that people with the same problem will see.
Solution for related problem
The BIOS appears to behave in a similar way to what is described above, only I'd suggest that the Lenovo code just checks for the presence of (at least) "Windows Boot Manager" in the UEFI firmware. It does not seem to force it to load. The Lenovo UEFI implementation in the BIOS for this machine will happily obey the specified BootOrder and load entries that are not labelled "Windows Boot Manager" or "Red Hat Enterprise Linux".
Although the implementation is definitely silly, this might alleviate some of the concerns about having to have an entry "Windows Boot Manager" or "Red Hat Enterprise Linux" that actually points to a GRUB2 loader for another distribution.
I've provided a full description of my findings over on the Lenovo community forums. I'm posting here because this is probably the first article that people with the same problem will see.
https://forums.lenovo.com/t5/ThinkStation/UEFI-Mode-installation-of-Linux-distributions-on-Thinkstation/td-p/1018555