Yeah, I can definitely understand that it's probably far faster (and cheaper, and reliable) to transfer the data in the shop with a USB cable in both directions

Yeah, I can definitely understand that it's probably far faster (and cheaper, and reliable) to transfer the data in the shop with a USB cable in both directions. In fact, it's probably fastest to have a small bank of hard drives that you can physically pull from the vehicle and swap out for a fresh one. You could probably pack a few hundred TB of storage into a unit that could fit in a briefcase and have it loaded with fresh map data and lots of room for logs.