You should be able to rename you new 2011 map gmapprom and replace it. Plug your unit into the PC and remove your existing gmapprom and store it somewhere safe then load the new gmapprom and restart your system should work fine if it is the unlocked version if not use fast unlocker v1.4 to unlock it first. the gmapbmap is your base map so leave it alone. Or as Texas Star said you could put it on a SD card but the above should work just make sure you save your original first (Cut/paste is good) Hope this helps you