Perhaps 2720 is different but Nuvi uses Region 48 for system that has the maps. What I have done before is, renamed 48.bin to 48.img. Used UltraIso to open the image, delete the map, then Save it in UltraIso. Then I manually added the rgn header with changed id to 48 to the 48.img. Renamed it to 48.rgn and flashed it with updater.exe. I can provide more info on the header if needed when I get a chance to look at it again.

I know in Nuvi this does flash successfully as I verified with read back. But in my case it didn't not fix my problem with 265w which probably has bad Nand area for NVRAM or corrupted badly.