Removed vTaskDelay() from the UART interrupt routine that receives data from transfer.py (see: motor git repository). This caused all sorts of problems with the stack getting exhausted. It was originally put in so the LED could be seen flashing as data got downloaded. However, the reason the LED didn't flash was this led::enable(1) wasn't called. This should be done but has to happen in main.c so need to add a c-binding to led::enable().
Please pick up the corresponding submission to the motor repository which has the tighter timing in the Python download program.