t959 dl mode.........................

When your Samsung Vibrant is in serious trouble (hang, very slow, or too many broken apps / file), you need to reset, getting into recovery mode. If you having trouble getting into recovery mode, chances are you are not holding down the power button log enough, or you are letting go of something too quick. By following this tips / tricks, you should have no problems to enter recovery mode:

1) START with your phone off

2) Press volume down AND volume up at same time, keep them pressed in the entire time, do NOT let go. I prefer to hold my phone in landscape, this gives me better control with my fingers.

3) WHILE holding down volume up and volume down, press and hold power button, DO NOT LET GO OF ANYTHING. You should be holding down volume up, volume down, and power, DON’T LET GO! HOLD ON… and proceed to next steps, dont let go!

4) PHONE will start, you will see the white Vibrant logo. STILL DON’T LET GO, volume down, volume up, and power all pressed.

5) White Vibrant logo disappears, still dont let go!

6) White Vibrant logo re-appears again for the second time. When the white vibrant logo appears the second time, let go of the power button, but keep holding down volume down and volume up.

7) Phone begins to enter recovery mode, you can let go finally.

To exit, select “reboot system now” and use your power button to select, you will exit recovery mode.

Source: http://androidforums.com/