@turboccc
Yes, I claim. There are a few small regions that contain OEM settings. This is true at least for nuvi 13xx/14xx, 37xx, 2xxx. They are too small to hold NVM settings.
Also I don't think NVM is in the flash at all, because in this case the writing speed would be slow and the flash would die too soon. I don't believe Garmin made such a bad decision. I think there is some kind of energy-independent memory inside ARM processor that contains NVM.
@lolypop000
What encoding did you use for OEM.xml? Make sure you save it with one-byte characters. I can't think up another reason why your perfect XML fails.