No you dont need to flash your drive. You can use the method of "Hot Swaping" It is much easier. All you do is open up your xbox or you can hot swap without opening your xbox 360. Then when the disk is spinning you take it out and put in the other disk. Message back if you want to know how to hot swap without opening your xbox.
**NOTE** None of these ways of hot swaping have anything to do on the computer. You just need to have a brain and some screw-drivers. The only thing you need that is computer related is the ISO Modded Disk.