Originally Posted by Buman
okay how can i get in download mode without an app ?
To boot into download mode on phones with ICS and up:
Turn off the phone, then press and hold the volume down key + the power key at the same time.
This should boot you into download mode.
If it doesn't, you may have to try different button combinations such as volume down + the home key + power key (holding them when the phone is off simultaneously to turn it on).
Also, on some phones you might have to pull out the battery (when connected to a USB) and do the combinations listed above for it to work.