Issue flashing MCU of SV08, Hangs at Detected USB device running Katapult

I am trying to flash the klipper via katapult on my SV08 and I am having big trouble. I've done the exact same process following this [guide](https://github.com/Rappetor/Sovol-SV08-Mainline?tab=readme-ov-file#step-6---stock-firmware-backup), and the toolhead flashed just fine, as expected. But the main MCU just hangs at "Detected USB device running Katapult". I've spent 3 hours now researching and trying different approaches but nothign seems to work. There is no webinterface open, I have also unplugged the default screen on EXP1 and EXP2. It just wont go past there and I cannot find anything wrong. Any ideas what I could do?