How do I deal with an automatic reboot following a cydia app install The tethered RedSnOw jailbreak for 5.1 worked like a charm.  I ran into a problem when I installed winterboard however.  Following the automatic reboot, I couldn't get my iPhone into DFU mode to use the "just reboot" function.  What am I doing wrong?
Well, good news for you. As from a few weeks ago, you are able to jailbreak your iOS 5.1 untethered, which eliminates the fact you've to "just-boot" the iPhone very time.

In order to do so, Jailbreak nation has published a very detailed and good tutorial on how to jailbreak your iPhone. I suggest you preform a untetheredjailbreak and try again. If things are still not working, please give some feedback with your errors so we can help you further.
Good luck!