I just downgraded it from 6.1.3 to 5.0.1 and I jailbroke it with the latest version of redsn0w, which means that I have cydia 1.1.8. I did all the essential updates, there are just 2 more updates (pcre and UIkit tools, these are not essential updates) and I installed icleaner pro to disable the OTA daemon and I installed corona 5.0.1 untether. Now, if I turn it off or reboot, cydia works,everything is fine but if press the sleep/wake button and home button at the same time and hold for about 10 seconds ( until apple logo shows up) and than try to open cydia, it crashes and so is safari and mail doesn't load. Now, after I turn off the phone after all this, when I open cydia, it works and so is safari and mail app. Basically, if I turn off the phone or reboot, cydia still works ( means that untether corona works) but if I restart the phone holding the 2 buttons, the jailbreak becomes tether until I turn off again. What is the problem?