Warning! You can only do this with benQ drives. Here is how to tell what kind of drive you have.
you need the middle one!
BenQ Drives look exactly the same as a LiteOn Drive. The only way to tell which kind you have is to take off your xbox 360 faceplate and look in the little hole under the disc drive. If there are 2 white wires inside, you have the correct drive otherwise you must open you're xbox
How to Hotswap:
I will be using cod 5 as an example. To install a modded version of cod 5 we must hot swap. To do this you must:
Make your xbox not auto run a disc. This can be changed in the system settings.
Hover over the PLAY GAME on your dashboard. Then, when you are ready, press Y and the open button at the same time. It should be frozen at a picture of a guy with his gun. then put your modded copy in and install to hard drive.
YOU MUST HAVE BENQ DRIVES OR THIS WILL NOT WORK. IF IT DOESNT WORK AND YOU HAVE BENQ DRIVES YOU'RE DOING SOMETHING WRONG!
Hope this helps. I did no discover this and i know it's sorta old!
+rep if i helped