I tried for three hours yesterday to jailbreak my aptv2. At first I got numerous codes when iTunes would try to install software. Finally I was regularly getting a 1604 error code. I tried different USB ports on my laptop, different USB micro cable. Tried shutting down itunes while it was in DfU mode and restarting iTunes. Nothing worked. I then tried to restore original software though iTunes using the same cable and laptop. It was able to restore it without any problems. From that I assumed it was not my laptop or USB cable. This morning I decided to try it on my desktop. I used the same cable and software and everything worked fine first try. I was up and running in no time. I then installed aTV Flash and everything is working great. I love it.
Also, thanks to wowever suggested using menu/down arrow first, then menu/pause play button. I was having trouble getting into DfU mode and that makes it work each and every time.