First of all, a special THANK YOU to POI FACTORY and especially CraigW. This is a first class site with first class people whose generosity is priceless.
I recently made queries about JCV files and my inability to access the hidden folder that held the JCV file in my Garmin DriveAssist 51. I had all my parameters in the CPU set correctly; however, I had not switched from MTP to MS mode in my GPS. Thanks to CraigW's advice, that was all that I was lacking. I can now access all files and folders on my GPS. FYI-my software version is 6.0, firmware: 9.00.00, maps version 2020.10 with JCV file of D3191280A @ 497,059.
Another note is when backing up the GPS to the CPU, one gets two entirely different backups-so be careful-the MS mode appears to be the complete and entire backup as opposed to an abbreviated backup in the MTP mode which I had originally thought backed everything up.
Thanks, again, to POI FACTORY and CraigW's generous input.

Kudos to all at POI Factory - a great site!