Hi. I've setup the Raspberry Pi 4b to the duet with the sbc-cable, but only recieve the error "Connection failed: waiting for Transfer Ready Pin".We have been fail-searching for HOURS and can't find anything wrong with the setup. The Raspberry is powered through it's own original power supply and the duet is powered through our printers power supply. We connected the duet to a raspberry 3 b+ and that works perfectly, but it's just so slow so we dont want to actually use it. The pin-outs on raspberry 3 and 4 are the same, so i dont get why the 4 doesn't work. We tried updating the firmware on the duet, but it did not help. The duet is not connected to anything else.
We followed this guide: https://docs.duet3d.com/en/User_manual/Machine_configuration/SBC_setup