Use this reflash files in order to upgrade your firmware if you are on 4xR ROKR firwmare already. Theese shx files will not delete any settings, skins, media, phonebook or sms messages. It will preserve all your settings except if you have custom bootscreen or CG1 patches applied (will be reverted to standart).
Use MultiFlashFlex from Motorola PST in order to flash it over. Do not flash over firware different than 4xR - it will not work!