Hi Thorhallur,
Sounds like your power cables are sat too close to your communication ribbon inside the machine.
You’ll need a T10 hex screwdriver to remove the side closest to the main encoder and then once you’ve done that, manipulate the cables so they look like they do in this post: Firmware update hangs, emergency update also hangs - #3 by otobot
Once you’ve done that, put the .upf on your SD card, insert it and power up the machine. You’ll see it boot up normally and you’ll be good to go.