So, iiuc the NXP code, modified as discussed above, should be expected to output messages on the “M4_0” UART, connected to SODIMM 144/146. Unfortunately these don’t seem to be available externally on the Iris V2.
Currently I have modified the firmware code to output on UART-B following hints from here.
This is working - I see RPMSG String Echo FreeRTOS RTOS API Demo....
But, no more than that.
I should expect to see Nameservice sent, ready for incoming messages... after sudo modprobe imx_rpmsg_tty has run on the Linux side, but no. Since UART-B is mounted by Linux, this may be the reason.
Anyway, it gives me some confidence that the M4 binary is running.
I will revert to the earlier M4 binary, which transmits on M4_0_UART now. Unless Toradex has a Torizon-compatible pre-built imx8x-disable-uart-b overlay available…
In any case, I am still not seeing any /dev/ttyRPMSG30.
Tim