Same-ish issue here. After installing kernel power, Nokia Multimedia Transfer (in b4 lolmacs) stops recognizing the N900 as a supported phone. Does kernel power change any USB identifiers?

A quick google search shows that application only cares about the model name to say it's supported or not. Looking at the stock .profile file for the N900, the only thing that could affect it is the "RX-51" part.

Well, I say this because I had issues with NMT that were solved by reflashing just the FIASCO image with the stock Nokia one, so who knows.