Ok, so i've changed the power supply using my bench supply that will provide upto 13.8v upto 70amps, and no change, Autohex will still not read the MCU through boot mode.
I've also just tried another 5 different DDE 73 units that i have in stock and still no boot mode read, all i get is the same error message.
Again, all will read ISN in normal bench mode, but none will write a new ISN, i keep getting the constant error 'failed to write ISN'.
I think the only way around this is if i can get hold of the CAS unit as there seems to be a problem with these DDEs in normal ISN write function, and also in boot mode. All other DME & DDE in boot mode seem to work, i have tried most types available.
Maybe 73 is an unlucky number!!!!