>> Not all of us can get cell phone coverage in the middle of nowhere, and not all mounts come with GPS enabled handsets,
>> and anyone using a mount where the handset is not needed is in even more trouble.
I think that is what the "Sync To Mount" in the ASIAIR interface is for. Just get an iPad with GPS, and you should be set. Some Android models also have built-in GPS.
Apple calls it "Assisted GPS," but the iPads do come with real GPS modules. iOS uses Cell towers (or WiFi) only to refine the coordinates. So they will work with no Cell coverage.
That being said, since we are dealing with Astronomy, one should be able to compute Longitude and Latitude quite precisely by using plate solving with the OTA pointed towards Zenith (zero Hour Angle). The Dilution of Precision from the iPads should be typical of what you get from stand-alone GPS modules. You just need a level to point the OTA to the Zenith -- I used to do this in the Dark Ages to align my Takahashi EM-11.
>> I also noticed you blocked off access to the USBC port. Is there a reason for that or is it power supply related?
>> Seems to be a waste of a perfectly good USBC port.
I don't understand why not having access to the USB-C port is a problem? Raspberry Pi 4 uses that USB-C connector for power only (just like the Raspberry Pi 3 uses the micro USB connector for power only).
Clear skies,
Chen