Comment # 8 on bug 1083037 from Michal Svec

(In reply to Jiri Srain from comment #6)
> Well, the generic code is written to MBR:

That seems to be correct:
f120205471a79e72e8c3f099a8e368f1  /usr/share/syslinux/gptmbr.bin
f120205471a79e72e8c3f099a8e368f1  /tmp/mbr1

> And, please, check whether your BIOS tries to load system from the right
> disk and whether it supports GPT partition tables.

It worked before with preinstalled Windows so I suppose it should work fine.

(In reply to Josef Reidinger from comment #7)
> parted -s /dev/sda disk_set pmbr_boot on

That didn't help either.