Use this tutorial if you want to learn how to successfully flash the brand new CM 12 Final Snapshot ROM for your Galaxy Premier device.

The CM 12 Snapshot is a stable Android 5.0.2 custom ROM and it is better to have it installed insated of the CM 12 Nightlies builds. Read more about this release at CyanogenMod's blog page here.

Read the following guidelines below starting the installation process of this new CM 12 Snapshot ROM for your device:

  • use this post only for the Samsung Galaxy Premier devices.
    - do not try to update any other different phones with the files that you will find in this post.
  • the phone that you are about to update has to be rooted and running a custom Recovery such as CWM or TWRP.
    - the installed custom Recovery needs to be updated to its latest version, so that it supports the latest Android 5.0.2 ROM installations.
  • in the tutorial you will find two extra preparation steps: the NANDROID Backup and the 'factory reset', you shouldn't skip them.
    - the NANDROID Backup creates a complete restore point for your phone, one that can be used in case your device doesn't boot in normal mode.
    - the 'factory reset' wipes clean the system OS partition, but it won't delete any files from internal storage.
    - 'factory reset' remove the old ROM, so that the new CM 12 ROM will be able to boot in normal mode.
  • if you wish to save data from installed applications, then you should use Helium for Android tool.
    - Contacts and People data can be synchronized with your default Gmail account.
    - don't try to use Titanium Backup in order to save data from your device as it doesn't support any CM 12 ROMs.
  • the battery charge level of your device needs to be over 50%, it will prevent the device from powering down while you are flashing the new ROM files.
  • this guide is for advanced users, we cannot be blamed in case you brick the device, nor in case you lose any important data files.
  • read the whole tutorial first and do not skip any steps if you want to install the new CM 12 ROM on your device successfully.

After you've read the info above you are free to continue to the installation instructions below.

How to flash CM 12 Snapshot Android 5.0.2 ROM for Samsung Galaxy Premier:

  1. Download the CM 12 zip file from here.
  2. Download Gapps for CM 12 ROMs from here.
  3. Move the files on your phone's internal storage and then disconnect the device from PC.
    - don't extract any of these two files.
  4. Power off the device.
  5. Next, boot it in Custom CWM / TWRP Recovery Mode.
    - you can do it by pressing Volume Up, Home and Power buttons simultaneously.
    - release the buttons when the Galaxy Premier screen flickers/ shows the Recovery menu.
  6. First thing that you need to do is to create a full NANDROID Backup:
    - CWM: select 'backup and restore'.
    - TWRP: select 'backup' option.
    - set an easy to remember file name and continue to the next step after the process is done.
  7. Factory Reset your smartphone:
    - CWM: select 'wipe data/ factory reset'.
    - TWRP: select 'wipe' options.
    - confirm the process.
  8. Start the CM 12 Snapshot ROM installation for your Galaxy Premier:
    - CWM: select 'install zip from sdcard', then 'choose zip from sdcard'.
    - TWRP: select 'install' option.
  9. Find the CM 12 ROM and confirm the installation process.
  10. When the ROM has been installed with success you can flash the Gapps zip too.
  11. Reboot your smartphone in normal mode after the installation of all files is done successfully.
    - note that the first boot process of this new ROM is going to take a while before it loads all the new files.
  12. Use your usual account info and People details in order to regain complete control over your smartphone once again.

These were all the steps you had to follow in order to complete the tutorial.

If the installation isn't completed successfully at your first attempt, and you are sure that your phone meets all requirements, then you should try to repeat the whole guide more than once up until the CM 12 ROM sticks to it. For any more help use the comments field below.

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