CynogenMod 13 (Android Marshmallow [6.0]) on Samsung Galaxy S3 GT-I9300. [21-12-2015]

The good news is this time Cynogenmod team is officially supporting S3 I9300. S3 did not receive CM12 officially but this time the device is back in the hunt. Well the ROM is still in initial stages of development and has some bugs but it is surely going to get better with every update. The nightlies from CM are out for this device. Follow the below steps to install CM13 on your Samsung S3 I9300-

PreRequisites: (click here to know How to Root Galaxy S3 GT-I9300)

  • Take a backup of your important data and settings using a custom recovery such as ClockworkMod(CWM) or TWRP to create a full image of the existing data. In case anything goes wrong then you restore your data.
  • Enable USB Debugging Mode on your Galaxy S3 GT- I9300 by going to Settings > Developer Options
  • Your Galaxy S3I9300 should be rooted with TWRM recovery installed. Click here for steps to install TWRP.
  • Make sure that the battery of your phone is at least 60% charged before proceeding to the installation guide.

Steps: [Note: Please use TWRP or above for flashing. The screenshots shown below are for reference only.]

  • Download the CynogenMod CM13 custom ROM and Google Apps Package (GAPS) on your desktop PC. Make sure you are downloading the right files available for your device.

LinksCM13 official link for Samsung S3 I9300 [Download the latest nighly available as per date]

Google Apps Package Download


These are ZIP files and should be saved as it is on your PC. (or download directly in your mobile device in SD card)

  • Connect your Galaxy S3 GT-I9300 device to the PC and copy the 2 ZIP files to the root folder of your SD card.
  • Disconnect your device from the PC and switch it off in order to boot it in recovery mode.
  • Turn ON the device by pressing and holding Volume Up + Home + Power keys at the same time.
  • The Galaxy S3 GT-I9300 will boot in TWRP recovery mode. Go to Backup option and take a full backup of your phone so that you can recover it to last backup in case of any issues.
  • TWRP-Recovery-BackupNext Go the Wipe option and perform a full data wipe using the Factory Reset option.



  • You can use the Volume keys to navigate between options
  • Power button to select an option in the Recovery Mode
  • Now in Wipe option, go to Advanced and select the Wipe Cache/Dalvik. (Wiping the Cache/Dalvik helps to avoid the boot loop issues)


  • Now go back to the Main menu and select the Install option. Select the location as SD Card and select the CM13 build ZIP file from the location you had copied earlier. Start the installation.
  • Now select the GAPS ZIP file and install it.


  • After Installation, go back to main menu and Reboot the device.
  • Your Galaxy S3 I9300 will reboot with Android 6.0 marshmallow. It may 4-5 mins approx for first time reboot.
[This is a device dependent process so please be careful while performing the installation. Same steps can be used for other samsung devices as well as long as you have the correct CynogenMod build file].


Please leave your comments and feedback.

I’ll keep updating the POST to include CM13 build updates as they come.

Thanks for checking out !

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  1. Martin

    Awesome! Thank you for this great tutorial 🙂

  2. Zola

    i like to get some help on installing Gapps. After i updated to CynogenMod 13 and then had to download then install caused my device to crash and couldnt started up wizard.

    1. Abhimanyu

      Hi Zola, I’ll be more than happy to help you. It’ll be better if you can mail me the problem and let me know which Gapps you used for installation? Email id- [email protected]

      1. Abhimanyu

        Hi Zola, I have replied you on the mail. Hope your issue is resolved.