Solved it myself, find the guide for updating BIOS without a battery here:
Also, updated with this method from 3.07 to 3.10 (from Windows, because I have no knowlegde of the CLI switches needed to make it work via UEFI boot), no issues there. Was my first update and I panicked for a moment when the machine just shut off after the update. But turning it on revealed everything was working perfectly.