I used the Ford Sync Update Downloader to downgrade (I was at 19274), and the downgrade was successful.
I then used the utility to update to 20136. After putting the flashdrive in the usb port, my infortainment screen said updating software, then about a minute later it said update complete, restarting. My infotainment then went black, and will not come back on. Any ideas on what went wrong or what I can do now?
Update: I think my issue is that I pulled out the flashdrive after I got the update complete message (I found some instructions on the site saying that it needs to be left in for the reformat process). At any rate, the screen went black and will not turn on.
Update 2: Here is some more info. I have a 2020 Explorer ST. I downloaded the NA version of 20136 with maps to the flashdrive.