The Samsung Epic 4G Touch has been plagued with a hang when changing between Sprint and Verizon towers in low connectivity areas. In some cases the issue actually required a device reboot to regain connection to data. This issue has been found by Sprint and and solved it in the form of a software update.
This update will also fix the issue of losing 4G connections when on a phone call. This update is rolling out in the form of an OTA (over the air) update that started pushing yesterday. As always the update will be pushed in phases so if you haven’t received it yet be patient it will appear.
Please let us know when you get the update if it fixes your issues and if any new ones arise.