Hi All, I've been working on developing CANopen communication using the inbuilt CANbus and additional transceiver units on an Udoo Neo Full. Got everything working fine, CANopen slave node is easy to read/write to, this is all being done using the A9 processor and the UDOObuntu OS system running the programs. The problem that I'm having is that when I come to start programming anything on the M4 processor (the M4 is enabled but in assuming just inactive at this point, and CAN open works flawlessly), even an empty sketch with nothing in it, as soon as I upload the sketch the CANopen stops dead and can be started again until the file /var/opt/m4/m4last.fw is deleted, and I reboot. If I enable loopback mode on the CAN and run the M4 process I can see that the program still runs in the background. Does anyone have any suggestions on how to keep the CANopen running whilst running a program on the M4? I'm assuming its got something to do with the standard pin assignments for the M4, but if anybody can point me directly at the root problem that would be awesome. Thanks.