soo... the usb port of my octopus broke of, and after 2 days research i got it working over uart. no mcu error anymore and also the temps show correctly (i frankensteined a printer.cfg).
now i am really hesitant to start messing with the config since i might blow up somehing. safest would be to download the cfg's my config references to. (i bought the printer second hand so i dont know all the parts and pints etc.)
also... i installed fresh mainsail, no ratos. could get it working with UART.