As a recent purchaser of a Phantom 3 Std. I wanted to be sure I had everything current as far as the firmware was concerned. When I got to the stage of selecting the FW version, I thought that the most recent dated version would be the one to select. As it turned out, that version name begins "P3X..." I downloaded it, and installed it on both the AC and the RC. When I tried to link the two, all I got was a continuous flashing of warning lights, and beeps; sometimes continuous, other times in sets of 4. Remembering that the other FW versions on the web-site had version names beginning "P3S..." I got to thinking that perhaps I had grabbed a FW version meant for one of the other P3 craft versions. That set me off seeking information on the possibility of "downgrading" the version I had installed to an earlier, hopefully, correct version. The dilemma I now faced is that nearly all the messages and videos I found involved using a thumb drive to plug into either the RC or the AC. Those comments are of no use to me as both my RC and my AC have micro-USB sockets only on them. Oh, how I wish there was some way to hook my RC and my AC directly to my PC and find out just which FW versions are on the two items.Then I could tell in an instant if I actually have a FW conflict, as noted in several entries in the TXT file. Even that is nor real help to me as I can not tell which is the latest of the entries.