Recently many people have fallen prey to the boot loop issue after installing a jailbreak tweak. The phone reboots, Apple logo shows up then goes dim and reboots. You can access your file system via SSH but cannot get into safe mode. I suffered this problem along with many others and it seems Cydia dev @saurik had received tons of emails on how to fix the problem. Luckily there is a fix where you need to remove two files on your device so your springboard can reload its file system.
First you need to SSH into the file system and find these 2 files
Once you find them don't delete them just in case
change them to
This basically renders them invisible, you can go and delete them later, always good to keep a backup
Once you have changed the name reboot.
Upon reboot you will notice all your stock apps are there and your installed cydia apps but NO appstore apps.
Just sit back and chill as iOS will slowly rebuild your apps on the springboard. I have over 300 apps on mine so it took a couple of minutes.
Then go back into iFile and removed the files you changed to .bak.
You can also use this method if you have jailbroken your device and Siri stops opening apps.