Is the USB device formatted for FAT32? When does the 31A0 error occur, at the beginning the middle or end of update process? I use the CTP11/CTP12 process so I can't say anything from experience about the CTP13/CTP14 process. When I load the new maps I bring up the Uconnect Nav home screen first and then plug the USB drive into the USB port. Seems to cause fewer problems with loading. I'm not sure what the 31A0 error code means but 31A2 means there's not enough storage space in the Uconnect to load the maps. I think there's a procedure posted somewhere on the forum for deleting Uconnect map files. After creating more space on the Uconnect you can retry loading the maps.
I have gotten an error message in the past (I don't remember the code) and the new maps would not load. The problem corrected itself when I loaded a different (later) version of the maps. Since your maps are the latest version (2023.20) you might try loading an older version (2021.20, 2021.30 or 2022.25) to see if they load successfully.
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