How do I update my wireless R9270 / R8170 levers?
These levers may be wireless, but they need to be wired to the rest of the system in order to allow firmware update via the mobile app (E-Tube Cyclist). If you do not wire them to the rest of the bike, updating over BluetoothLE/ANT is out.
The mobile app communicates with the Di2 system through the rear derailleur, and it cannot connect to the levers directly. Furthermore, it seems the levers are only capable of receiving a limited set of signals or instructions.. and updating firmware is not part of that.
I have written a guide on updating the firmware on these levers, you can find that right here:
SM-PCE02 users - no problem
This process is also described in the update guide.