Samsung Galaxy S 2 (GT-I9100T) Firmware Overview
What is the latest GT-I9100T firmware?
I9100TDVOF1, released August 17, 2015 for region TEL with Android 4.1.2. The archive holds 4 official builds for this region.
Is the Samsung Galaxy S 2 still getting updates?
Most likely not: there has been no new firmware since August 2015, so Android 4.1.2 is the last version this model got. The final builds below are still the best choice for a clean reinstall.
GT-I9100T firmware for region TEL
How to Flash GT-I9100T Firmware
Put the Samsung Galaxy S 2 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.