Turns out, it boots just fine. Or maybe it does now. There was a cap next to the CPU halfway detached. I resoldered it on first sight. Maybe that already fixed the issue.

I don't have an Amiga mouse. So we quickly whipped up an adapter.
Code can be found here
https://github.com/glitterkitty/Arduino-PS2-Mouse-to-Amiga-Adapter

Been working on the Amiga with Luna PurrpleFoxy

Putting it back together for now, since we ran out of time. It still got numerous issues. The keyboard works only partly, a RAM test detects only 512kB of the installed 8x 4bit x256, we have no mass storage solution, and no proper video cable. Time to spend some money on this.

Do you have any suggestions for upgrades? Been considering the PiStorm.