Updated the firmware on my RNS 510. Took about 45mins.
Starting at Firmware version 3970:
System is turned on with no keys in the ignition and update DVD inserted:
Press ok and update starts. System reboots a couple of times in the process:
Once update all finished, the system restarts and then reset the system by pressing <,> and the star button simultaneously. Now running version 4020:
Still got the update to 5269 and the V10 maps to install but need some dual layer DVDs for those maps first.