Just wanted to post and say I successfully upgraded to 40.1 on my UAQ unit, part number 68331631AK. It was on 22.66 when I pulled it out of the salvage yard. Per
@Mpgrimm2 's recommendation, I upgraded to 28.3 first. I included the map files from the 21.9 upgrade file, just to see what it would do. You can see in my attached images the database name/version before and after the upgrade. They both say 17Q2 in the name so even though there is some additional added text after the upgrade, it "appears" to be the same database version that was on my radio already.
I've seen several posts asking this but never saw a firm answer regarding how the files should look on the USB drive when performing the update. I posted a screenshot of how the ROOT of your USB drive should look when you're ready to upgrade. When you open your USB drive you should have the VP4R_Update and map_package folders. If you are not attempting to update your map files, then the only folder you should see in your USB drive is the VP4R_Update folder.
I also wanted to add I was having some trouble with the USB drive I was using. It was a 128GB USB drive, but I had it partitioned down to 16GB formatted as FAT32. Every time I would plug it into the USB port in the truck, nothing would come up and on the Media screen on the radio, it would say USB Error, Reinsert. Well, I didn't have another flash drive with me, but I did have an empty 500GB USB hard drive. I deleted the existing partition and created a new 16GB partition and formatted as FAT32. Loaded the radio files and plugged it into the truck and the update prompt appeared almost immediately.