ipod touch 4th gen doesn't turn on My ipod touch 4th gen has this CYDIA, I accidentally uninstalled one file from it. After that, the ipod crashed and never turned on since then. 

It turns on (showing apple logo) for 10 seconds, then turns off. After 2 seconds, it turns on again. Whole process repeats. Until battery's exhausted.

I tried this:

Hold the power button for 2 sec. Without letting go of the power button, press and hold the home button for 10 sec. Let go of the power button but not the home button for another 10 sec. 

It connects the ipod to itunes, itunes detects the ipod. However, it has an error message " the ipod software update server could not be contacted".
You have turned your iPod in DFU mode, now you can do one of the following things to turn on your iPod touch back


Press power and home button of your iPod simultaneously for 10 sec. Then press power button until apple logo appears on screen. If this does not works then follow step 2.
Take your iPod again to DFU mode using your step -->

a. Hold the power button for 2 sec. Without letting go of the power button, press and hold the home button for 10 sec. Let go of the power button but not the home button for another 10 sec.

b. Then by pressing the home button connect your iPod to the iTunes. It will ask for restore. Do the Restore.