casainho said:For testing, I think you can disconnect the wire that power up the motor controller from the display, then, connect directly that wire to the battery voltage. That way the system will work but you will need to cut off the battery power to turn off the system.
Good thought - I disconnected the orange (LCD) and red (motor) leads from each other, and joined the red (motor) end to the brown (LCD)/blue (motor) cable join. I left the now free orange (LCD) lead disconnected.
I still need to hold the power button down (so it does not progress to the next screen - at least I now know this is by design) but the negotiation of firmware versions happens much quicker (presumably because the motor controller is already running and waiting for a signal).
The motor however gives a small kick - this did not happen before. Is the bootup sequence reaching a slightly further state?
FWIW, I have also tested continuity between the cable joints and the 8-pin HIGO-B8 socket, so I am confident the joins are good and that the cable insulation color scheme is as expected.
Thanks again for your help!