touch pro hardware flashing question

[zikronix]

Ok,

Its been a long time since ive been in this flashing game Any who I have a sprint tp which i flashed for vzw... but i have a couple of general questions not related to that.

I will be using the sprint on vzw as my example.

So if you have a phone that has the stock rom on it...which includes the pri, etc. then how come when you flash it to the vzw rom, and even flash the vzw pri, then how is it that we still must use modified prl.

I would think if it was a full flash the phone should just work as in i shouldnt have to use a modifed pri, or modified prl.

I hope this makes some sort of sense. I guess i really dont under stand what values are written that the rom and pri dont over write that makes it require the use of modified files.