you not need any .bak file for operate my device option
1. connect your tomtom to PC and start HOME and download files when asked
2. shut down HOME and patch it with [Only registered and activated users can see links. ]
3. try again with HOME...
when you start HOME it tell you wrong software version, that is not do any harm for you just cancel update
if you use .bak file then operate my device option maybe show you can not open this map
you must choice smalest harm for you....