You might free up a bit more but defniitely not the full 4gb. It's liek when you buy a laptop from bestbuy, it always comse with a bunch of shit from Bestbuy and say Dell that you don't want. In order to get rid of it, you can format your harddrive and install windows just by itself, without the shit that came with the computer and you'll probably have freed up a good chunk of storage from before. However, you still installed Windows which is a few GB in itself. So now, think of Bestbuy as tmobile and Dell as HTC, both of them put their shit into the phone. Rooting is equivalent to reformatting and installing windows byitself, except you're reformatting your cellphone and installing android OS. Android OS still takes a few GB!