The official CyanogenMod 10.2 Nightly is now available to be flashed on AT&T Samsung Galaxy S2 model i777. CM 10.2 nightly, based on AOSP Android 4.3 Jelly Bean, will bring tons of new features on your Galaxy S2. Follow this tutorial and upgrade your Samsung Galaxy S2 i777 to the latest Android with CM 10.2 in no time!

Prerequisites to install official CM 10.2 nightly on Samsung Galaxy S2:

Downloadand install USB drivers for Samsung Galaxy S2 on your computer.Enable USB debugging mode from developer menu.Your AT&T Galaxy S2 should be unlocked and rooted.You should have a custom recovery tool like TWRP or CWM installed on your Galaxy smartphone.Backup anyimportant databefore going forward for the tutorial.Ensure that your Galaxy S2 i777 carries more than 70% of charge.

How toinstall official CM 10.2 nightly on Samsung Galaxy S2:

Required files: download the official CM 10.2 custom firmware file fromhere. Also download the Google Apps Package for your smartphone.Save both the files on your computer; do not extract the contents.

Connect your Samsung Galaxy S2 i777 with computer using a USB cable and copy the custom ROM and GApps files on the phone's SD card.Disconnect your AT&T SGS2 from computer when the copy is done and power it off.Reboot your smartphone into recovery mode.Take Nandroid backup of your current OS:Backup and Restore>Backup.Now perform data wiping tasks: selectwipe data / factory reset,wipe cache partition, and finallywipe dalvik cache.Return to the main recovery menu and selectInstall zip from sdcardfollowed bychoose zip from sdcard.Locatethe downloaded firmware file and confirm installation.Once the CyanogenMod custom ROM is successfully installed on Samsung Galaxy S2, repeat the above step but select GApps file this time.When done, reboot your AT&T Galaxy S2 to boot into the newly installed official CM 10.2 Nightly custom firmware.