Just jailbroke with redsn0w on my iPhone 4. 4.3.1 Cydia showed up, but with a white icon. When I open it, it crashes instantly. Tried downloading it again. All I clicked was "install cydia" on redsn0w. Anyone know the problem? Thanks in advance.
Try redoing the JB, don't restore or anything just run redsn0w again and perform the JB over itself to see if there are some messed up files that might get restored.
