A couple of days ago I loaded the Western US on a 2 gig SD chip for my wife's mPower. The CF card, my wife received the other day with the program on it, had the State of Washington already loaded I then loaded Oregon on that chip as well, works wonderful. The question is, how do you tell the program to get its map information from the SD chip, not the CF chip or can you? We both read through the manual and can't seam to find what we're looking for. I'm sure we have read over it, but could someone enlighten us. Maybe it's the impossible dream.... The reason she wants to use the SD chip is that she has books loaded on another CF card and would like eventually to put that into the PCI slot. I'm assuming here you don't have to have the CF card that came with the program, in that slot whenever you using the GPS. I also want to commend Sendero on a fantastic job they have done with their instruction for loading the program and getting it up and running. It took 2 weeks to get the same spot with the Trekker vs 30 minuets time with the Sendero. You have saved another marriage. Well worth the wait of 3.5 months to receive the system. I'm as excited about her new GPS as she is. We love our toys! Craig Phillips