- Do you have DSP or analogue speakers, if so, how many and what sources? Before re-flashing, try re-typing the unit to the closest match to your system, if that clears the fault, you can try re-typing again, back to your currently stored type. Instructions for re-typing on p. 63 of the 568 User Guide

- If the above doesn’t work, make sure you have the correct USB-Serial converter Wiki.

- You will need a copy of the legacy config program here.

Then you’ll need a copy of the flash upload instructions, which hopefully a friendly Hitchhiker or dealer might be able to supply if you ask. I don’t have those to hand at the moment.