UPDATE:
Exec summary: I have successfully updated the software on my Tucson PHEV but, despite the update page clearly stating "You can connect Apple CarPlay and Google Android Auto wirelessly without a USB cable!" my car says no.
The procedure I followed to upgrade:
- Download the Navigation Updater app from this page - https://update.hyundai.com/US/EN/updateNoticeView/GnwBK4
- Launch Navigation Updater and, in the first screen select your vehicle
- Plug a USB key (at least 64 GB) into your computer and select it in the next screen - this was the key change from my previous failed efforts which actually followed Hyundai's Instructions
- You will be warned that the app will erase and format your USB key. Read carefully to ensure it's referring to the USB key you are using for this purpose and confirm
- The app will simultaneously download the update files and copy them over to your USB key
- When finished, eject the key, plug it into your car, turn the car on (accessories on is enough) and follow the prompts to update.
In my case, the download/copy took about 30 minutes (300 Mb service) and the install about an hour.
Unfortunately, although the update was 100% successful, my car still tells me this:
Now, I am in Canada, and it may be that despite the page I was directed to by Hyundai Canada promising wireless CarPlay, it may not yet be offered here. I would be interested to hear whether it fixes that deficiency in American models.
As for why the method detailed above worked to update the software, my guess is that a finder copy may have put additional files on the key that frighted and confused the Tucson's operating system, whereas a key that was formatted and populated by the Hyundai app did it just the way the car wanted it.