Why does my jailbroken iiPhone (iOS 7.1.2) turns on and then restarts?

[iMore Question]

after it shows the apple logo i switch on and it does the sme thing again

 

[Just_Me_D]

Are you saying that the device keeps restarting itself? If so, you may have to put the device in recovery mode and restore via iTunes, but you will lose your jailbreak.

If you can't update or restore your iPhone, iPad, or iPod touch