Samsung Galaxy Mega 7.0 (SM-T2556) Firmware Overview
What is the latest SM-T2556 firmware?
T2556ZNUANL2, released January 13, 2015 with Android 4.3. The archive holds 3 official builds across 1 region (CSC). Each one is the full stock ROM (flash file) for Odin, not an OTA patch.
Is the Samsung Galaxy Mega 7.0 still getting updates?
Most likely not: there has been no new firmware since January 2015, so Android 4.3 is the last version this model got. The final builds below are still the best choice for a clean reinstall.
All SM-T2556 firmware builds
How to Flash SM-T2556 Firmware
Put the Samsung Galaxy Mega 7.0 into Download Mode, load the BL, AP, CP and CSC files into Odin on a Windows PC and press Start. Use HOME_CSC to keep your data, CSC for a full wipe.