Another noob here.... I have been looking everywhere and can't find how to change the OS on my PCM so that I can use an XDF that has already been made. I'm not super tech savvy but I do know I need a matching XDF and OS. I have seen lots of people say that you must change OS number but nowhere can I find somebody explaining how to change it. I have an LM7 from 1999. 4896 PCM. 9379910 is my OS. I also believe this is a P01. I am using LS droid and tuner pro. Thank you