Crash Reporter is a small app that records the logs from all the crashes on your device, no matter if you bought the app in the App store, or on Cydia. Crash reporter will show how many times the app has crashed; what the primary, secondary, and tertiary suspects are; and how to report any bugs. Overall, the app can be very technical if you dive down into the menus, but if you stay towards the surface it’s very user friendly. Crash Reporter has gotten me out of tons of jams on my jailbroken iPhone, allowing me to get out of several crashes without having to restore my device.
Crash reporter is free in Cydia and can be found by just search, no new sources required; head out and grab it!