USB Jig

What does USB Jig do?

- Get into download mode (main function)
If you soft brick your phone, you can force into download mode using USB jig and reflash new kernel or ROM. As far as i concern, there are few ways to force into download mode, however this is the most simple way to get into it. If USB jig doesn't work, i don't think other method will work either.

If your phone is hard brick, i don't think this will work.

- Remove the yellow triangle
Once you flash your s2 with insecure kernel, a yellow triangle with exclamation mark will appear at boot splash. USB jig can do the trick to remove it for you. (i know flashing S2 with original will remove the triangle as well, but i just wanna point out USB jig function.)

- Reset Odin counter/Reset custom binary counter
If you flash custom ROM into your s2, the binary counter will record it, even after you unroot your phone and set everything to its original, Samsung can still keep track by referring to binary counter. No worry, USB jig will clear the counter. However, some manage to get away with it and still get a warranty, but better to be safe than sorry.