Only way to retrieve information is to fit both electronics module and ISS one at a time on another HP 500 designjet to back up information from good unit. this is the case if you are repairing a HP 500ps, 800 and 800ps printer as the parts are standard item for all.
You some times get this error 1:10 when first boot up printer after replacing the electronics module, after powering the printer on from taking power lead out, power up as normal, this will boot up ok if not lost identity!
Hot tip! I managed to reset electronics module after fitting to a different hp 500 designjet printer of the same setup taking the ISS connection off allowing it to fault, then reconnecting cable and powering back up. This set electronics up with the information stored on the ISS.
Ones identity was the same re-power the HP 500 designjet printer in to normal operation!