Here's where we want to go.
Make sure you have backed up that 'Western_and_Central_Europe_2GB' folder to a second location. I say that because Home will overwrite that folder in the future if you do another backup. It does not do incremental backups and does not use a separate folder each time. Protect that, and you can recover almost anything.
Start by performing a FAT32 'Full' (not 'Quick') format of your unit. You'll need to connect it, so when Home appears, just close it out with the "X" for now. We'll get back to it later.
Once the format is complete, disconnect your XXL with a proper Windows logical USB disconnect (use the icon in the systray) and reconnect it again. This time, when Home appears, it's going to suggest some firmware to you since it won't find any on the unit.
Accept whatever firmware is offered by Home and get it installed on your unit.
Perform a proper logical USB disconnect using Home (I use the little down arrow in the lower right of the Home screen), physically disconnect your unit and connect it again.
IF Home then offers yet more firmware updates, install them with the above two steps until it ceases to offer any firmware updates. In the end, I think you will finish at v9.103.
At this time, you can minimize (not close) Home to get it out of your way, and go to your PC backup copy of the Western_and_Central_Europe_2GB map folder. Copy that entire folder over in to the root of your XXL.
Bring Home back to the fore and again, do a proper USB disconnect with Home.
Disconnect your XXL from your PC and shut it off. Restart your XXL and tell us how you're doing.