Update AT&T Galaxy S2 I777 to Android 4.2.1 CM10.1 Nightly Jelly Bean firmware

Update AT&T Galaxy S2 I777 to Android 4.2.1 CM10.1 Nightly Jelly Bean firmware... Now user can update AT&T Galaxy S2 I777 to Android 4.2.1 CM10.1 Nightly Jelly Bean firmware.

Here is the complete tutorial how you can it. Before going to forward, do not forget to backup all your personal data and apps.

Installed all your USB DRIVERS FOR AT&T Galaxy S2 I777 through PC. Some things you should keep in mind.

1. Enable the Debugging Mode. By enable the debugging mode you can connect own android phone or tablet with PC.

2. You should check your battery. Your batter should be 80% to 85% charges. If your phone or tablet will be off during flashing ROMs or installing mods and updates due to low battery. Then your Phone or tablet will be dead permanently.

3. As, i told you. You should back up all your date. You will need it for new ROM.

4. Your tablet should be Unlocked. 

Now we move forward and important part.

Here is the complete detail in different steps.

Read the all steps carefully.

Step 1
Download Android 4.2.1 CM10.1 Nightly ROM and Google Apps zip for Galaxy S2 to your computer.

Step 2
Connect and mount your Galaxy S2 USB memory on your computer using the USB cable.

Step 3
Now copy/paste the downloaded Android 4.2.1 ROM zip and Google Apps zip files to your SD card. Make sure the files are in the SD card root (not in any folder).

Step 4
Then turn OFF your phone and disconnect from the USB cable.

Step 5
Now to get in the Recovery Mode. Switch ON the phone while pressing and holding Volume Up + Volume Down + Power buttons, continue to hold all three until the screen flashes, then release all buttons.

Step 6
In ClockworkMod recovery, perform a full data wipe first. Then scroll down to “flash zip from SD card” and press the Power button to select it.

Step 7
Press the Power button again and select “choose zip from sdcard”.

Step 8
Now using your volume keys, navigate to the Android 4.2.1 ROM zip file that you copied to your SD card and select it using the Power button. Confirm the installation on the next screen and the installation procedure should start now.

NOTE: Repeat this step for the Google Apps zip file as well.

Step 9
After the installation completes, go to “+++++Go Back” and reboot the phone by selecting “reboot system now” from the recovery menu. The phone will boot now and it might take about 5 minutes to boot on your first time. So, please wait.

That’s it! Your AT&T Galaxy S2 should now have Android 4.2.1 CM10.1 Nightly Jelly Bean installed on your phone! Go to Settings > About phone to verify.

Now AT&T Galaxy S2 I777 updated to Android 4.2.1 CM10.1 Nightly Jelly Bean firmware.