Up Squared dead after BIOS update

I finally found a use case for my Up Squared I got from Kickstarter (E3940, 1.8GHz, 4GB RAM, 32GB eMMC) as a low end desktop PC running Ubuntu.
I thought it would be a good idea to update the bios as it was still on 3.2 (haven't touched it since I got it a few years ago)

I updated to 4.0 first, which worked somewhat OK, grub got messed up but I was able to boot into BIOS and UEFI shell.
I then updated to latest 6.1 and it claimed it was successful but now it won't boot anymore.
The blue power LED stays on and the ethernet link light flashes once but no HDMI out.

Is there anything left to try before buying a SPI programmer?
Can you guys recommend a cheapo SPI programmer?

Thanks