Install Android 5.0.2 Lollipop CM 12 on AT&T Galaxy S3 I747

CyanogenMod 12 is now being updated to the Android 5.0.2 Lollipop, and most of those device which received the update of CM 12 while it was on Android 5.0 Lollipop are now receiving the next update. Although there were some device which didn’t receive the CM 12 update before, and now they are getting one. AT&T Galaxy S3 is one of those devices, which weren’t there while the CM 12 was in its early stages and now since the next update has made the ROM more stable and smooth, this device is getting its update with complete support.

For this ROM, you’ll need to flash the Modem separately, if by any chance you get the Signals problem or Wi-Fi disturbance, otherwise just go with the flow and install the ROM. CM Superuser is also added in the ROM, so there is no need to flash it separately. In this article, we will show you how to Install Android 5.0.2 Lollipop CM 12 on AT&T Galaxy S3 I747. If you are interested in Other ROMs, you can visit our Custom ROMs section or you can install this ROM on your AT&T Galaxy S3 I747 by following our tutorial below. This is not an official release from Samsung but a Custom ROM. Your device must be rooted. Let’s go through the ROM features and early preparations and then flash this ROM

Install Android 5.0.2 Lollipop CM 12 on AT&T Galaxy S3 I747

Early Preparations:


The methods involved in flashing custom recoveries, roms and rooting your phone are highly custom and may result in bricking your device, and has nothing to do with Google or the device manufacturer that is Samsung in our case. Also rooting your device will void its warranty and you will be no longer eligible for any kind of free device services by the manufacturers/warranty providers. In case of any mishap we may not be held responsible. Follow these instructions to the letter to avoid any mishap or bricking. Make sure that whatever you do, you are doing it at your own responsibility.

Downloads Required:

CyanogenMod 12: Link

Google Apps: Link

How to Install this ROM:

  • Connect your device with PC.
  • Copy and Paste the Above zip files to the root of your sdcard.
  • Open Recovery mode. How?turn it off and wait for 10 seconds. Turn it on by pressing and holding Volume Up + Home Button + Power Key simultaneously.

CWM/PhilZ Touch Recovery Users.

  1. Back-up your ROM using the Recovery.
  2. To Perform a Back-up, Navigate to Back-up and Restore on Next screen, Choose Back-up again.
  3. Go back to Main Screen after the Back-up is complete.
  4. Navigate to Wipe Data/Factory Reset and Do it
  5. Then Navigate to ‘advance’ and choose ‘Devlik Wipe Cache’, so you won’t get in any bootloop.
  6. Navigate to ‘Install zip from sd card’ another windows will open in front of you.
  7. Select ‘choose zip from sd card’ from the Options.
  8. Select the CyanogenMod file and confirm the installation on next screen.
  9. Go Back and Flash Google
  10. Then choose whatever you like from the Options and Continue
  11. Once the Installation is Over, Select +++++Go Back+++++
  12. Select Reboot Now to Reboot the System.

TWRP Users.

  1. Tap On Back-Up and Select System and Data
  2. Swipe the Confirmation Slider
  3. Tap on Wipe Button and Select Cache, System, Data.
  4. Swipe the Confirmation Slider.
  5. Go back to Main Menu and Tap Install Button.
  6. Locate the CyanogenMod 12, and Swipe the Slider To install it.
  7. Once the Installation is Over, you will be promoted to Reboot System Now
  8. Select Reboot Now to Reboot the System.

Solve Signature Verification Error:

  1. Open Recovery.
  2. Navigate to install zip from Sdcard
  3. Navigate to Toggle Signature Verification and Press Power Button and See if it is disabled or not. Disable it and then Install the Zip without any Error.

First Boot might take up-to 5-minutes, so let your device rest for 5-minutes as you do something else.

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