You can download the firmware updates from the Nikon site:
Fixed in D500 firmware version C1.02
- Addressed an issue that sometimes caused errors with certain UHS-II SD memory cards. As we were able to confirm that these were read errors arising not in the camera but in the cards themselves, we addressed the issue with a work-around that switches temporarily to UHS-I mode when a card-side error occurs in UHS-II mode. The camera switches back to UHS-II mode when turned off and then on again or when the standby timer restarts. Card-side read errors may still occur after the update, albeit very infrequently.
Fixed in D3s firmware version A1.03/B1.02
- The battery level indicator would on rare occasions flash if the camera was turned on with Clean at shutdown or Clean at startup & shutdown selected for SETUP MENU > Clean image sensor > Clean at startup/shutdown.
- Two different pictures with the same file number would on rare occasions be recorded to both memory cards if two cards were inserted with Overflow selected for SHOOTING MENU > Slot 2.