Hi,I'm thinking of installing the OTA_Bravo_Froyo_HTC_WWE_2.09.405.8-1.21.405.2_release4dua3bcrut4wrv30.zip file unto my unlocked,unbranded and unrooted phone.But if the installation goes wrong for example,if the signal bars on the phone are lesser than usual or if it doesn't have the radio v5 thingy on it or GPS issues e.t.c,how do i reinstall the original 2.1 version back onto the phone?Thanks