Last time we heard of the Sprint Samsung Galaxy S II Epic 4G Touch in relation with a software fix it was about a user leaking the patch which tried to solve the signal loss problem. Now Sprint made an official refresh available and should be hitting devices as we speak.
The new version, S:D710.0.5S.EK02, is dated December 7 and should be fixing the 4G Sprint hotspot disconnecting issues users were experiencing while in a phone call. Also, a fix for the radio losing signal until reboot is also in the changelog. Make sure to check for the refresh and apply it as soon as it is available for your phone.