The cabs you tried will not work since they are designed for a different XL version. Yours would be this one:
But since there are so many XL models, I would update through TomTomHome in order to obtain the proper version 8.**** and then patch this navcore. You can use that with a WE or US+CDN or US+MEX 845.2666 map (or 850.2820 if it is around yet) which will fit on 1 GB.
If you want to run an 8.562 version, download the SE version by TTUser. This can be configured to any device, just read the file readmenot.txt for the correct switches.