The trouble with Vibrant is that it cannot be rooted if it is running Froyo. First, it has to be downgraded to Eclair via Odin, and then can you apply the root update file. I wasn't even able to root it via the universal root tutorial.
For the sake of others, I will now list the steps of rooting the Samsung Vibrant in case it is running 2.2 Froyo.
1. Download Odin, this PIT file and this tar of the Stock 2.1 Eclair.
2. Put the phone into download mode. The best way to do that is to turn off the phone and reinsert the battery. Then press both volume up and down and connect the USB cable while holding them.
3. Let all the drivers install. This won't work till all the drivers are automatically installed.
4. Open Odin. You should see a COM port connected and colored yellow.
5. Select the PIT file, and put the tar file in PDA.
6. Re-partition will be checked and that's okay.
7. Click start.
8. Ideally, it should start and complete in about 5 minutes. (If it hangs or gets stuck at setting up connection, try again with different ports. For me, it didn't work for quite some time. Then I tried to restart the phone but it showed the triangle of death [a phone and a computer with a yellow triangle in between]. But when I tried it again with that screen, Odin worked the first time.)
9. When booted into Eclair, enable USB debugging from Applications> Development.
10. Copy this update.zip to the INTERNAL MEMORY. This file will root the phone and install Superuser and BusyBox.
11. Also copy this update.zip to the INTERNAL MEMORY. This file will install Clockworkmod Recovery. Obviously both files should be applied separately because at a time only one file named update.zip can be placed.
12. To install an update, boot into the recovery. To do that, turn off your phone and then turn it on by holding the volume down and power buttons. In the stock recovery, select "reinstall packages".
13. Repeat above step with Clockworkmod Recovery update.zip
Congratulations, you now have a rooted Samsung Galaxy S Vibrant T959! Feel free to flash new ROMs!
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