I don't know if this helps however whenever I downloaded a tweak or application from Cydia that caused my iPhone or iPad to crash here's what I did. I first held the power button down and the home key until the device shuts down. Then when i reboot i hold the power and volume up key the entire time it rebootes. When it boots it like it was before the jail break.. (Not safe mode) all the settings for yout apps/tweaks are gone but you can still open cydia and uninstall apps. I just unstall ones i think migh be causeing it. Then reboot if it dont fix it i repeat the process untill i uninstal the problem app. Sometimes its not the last app you installed before the crash.. My iPhone5 does not like dashboardx for some reason and caused it to fail to boot and had to do the above process. However i didnt think it was that app because it ran fine for a day or two. I hope this helps
