A few weeks ago a method for achieving S-OFF on the Rezound was released. This allows for all sorts of good stuff like flashing unsigned custom images as well as other mods. However with new development often comes issues. Firmware updates often break root, new rom bases can kill a theme, and in this case turning off security forked the custom recovery especially the nandroid backup function and sdcard mount function. Luckily there is now a fix for the Amon Ra Recovery thanks to "carm01" of Xda. It should be noted that the nandroid backup fix will require you to wipe the sdcard twice so before moving forward it is highly recommended that you backup your sdcard. It always sucks to erase that thing and then later remember you had all the daughter's birthday pictures stored there. Once you have your backup of the sdcard you will reflash the recovery, wipe sdcard, boot back into the rom, then erase the sdcard again. The sdcard mount fix requires you to format the sdcard using default settings. This fix is said to work for most, but may not work for all.
via XDA