Probably vendor proprietary. I know of no standard PGN for firmware or calibration. I have found a 2009 doc that talks about future cross vendor calibration, but I don't have access or $$ to view the official list of PGNs. I could possibly capture an update but don't think it worth my time or risk of bricking my devices. Even with my actisence PC-N2K gateway I'm not ready to tackle it. Maybe a remote to drive the AP remotely as Rays remote is expensive and is seatalk-1 only so also requires a bridge to get to N2K
Les
Les