Update Galaxy S3 Neo I9300I to Android 5.0.2 Lollipop with CyanogenMod 12 ROM

Samsung Galaxy S3 Neo, dual-SIM Android smartphone launched in April 2014, with the exact same specifications of Galaxy S3. Galaxy S3 Neo has a 4.8 inch HD screen, 8 MP camera and 1.5 GB RAM and came with  Android 4.3 Jelly Bean but Samsung has updated it to Android 4.4.4 KitKat. Many Samsung devices received the Android 5.0 Lollipop recently but there is no news from Samsung that when they will update the Galaxy S3 Neo to Android Lollipop.

But the developer community is working hard to bring out the latest Android version via custom ROMs. So those who are waiting for an Android Lollipop custom firmware then here is a good news that an unofficial CyanogenMod 12 build for the Galaxy S3 Neo (GT-I9300I) released by a senior XDA member Rox recently. This built has no major bugs that can be considered highly functional stable (excluding some minor bugs) and you can use it as a daily driver, according to XDA. But remember that this ROM is still under development and some features might be missing in this ROM but that can be ignored.

The CyanogenMod 12 ROM is based on the latest version of Android, 5.0.2 Lollipop build for the Galaxy S3 Neo GT-I9300I that brings a few bug fixes and stability enhancements. So if you want to update Galaxy S3 Neo I9300I to Android 5.0.2 Lollipop with CyanogenMod 12 ROM then we’ve a step by step detailed guide below. Go ahead and follow these instructions carefully.

image credit: androidrootguide.com


This ROM is under development currently so you may face some bugs. This unofficial CyanogenMod 12 ROM is only limited to work with Samsung Galaxy S3 Neo I9300I. Don’t try to flash it on any other variant, as a result it may brick the device.


AndroidXDA.net will not be responsible for any kind of damage or lose occurred into your device during or after the installation of unofficial CyanogenMod 12 ROM. Proceed at your own risk.

Changelog: (27/12)

  • CM Sources update
  • Fixed bootloop problem
  • Fixed RIL on GT-I9300I
  • Fixed Wi-Fi tether
  • LPM Charging fixed
  • Updated adreno and widevine blobs
  • Updated blobs - Camera problems should be fixed
  • Added support for GT-I9301Q

Minor Bugs:

  • Audio in calls on 2nd SIM (GT-I9300I)
  • Some devices have non-working camera because they have a different sensor – Fix available for this
  • NFC (Can’t be fixed, lack of sources)

Before Getting Started:

  • Make a proper backup of all your required data via custom recovery on the Galaxy S3 Neo.
  • Download and install correct USB Drivers on your PC for the Galaxy S3 Neo.
  • Enable USB Debugging Option on your device by navigating to Settings > Developer Options.
  • If you can’t see the Developer Options then go to Settings > About Phone and tap on Build Number several times until a message appears saying “You are now a Developer.” Now enable USB Debugging Mode from Settings > Developer Options.
  • Your Galaxy S3 Neo should be rooted with the latest recovery installed, otherwise you’ll not be able install this ROM.
  • The battery level of your Galaxy S3 Neo should be at least about 80% before proceeding.

Download files

Steps to Install Android 5.0.2 Lollipop on Galaxy S3 Neo I9300I with CyanogenMod 12 custom ROM:

Follow the given steps to install the functional CyanogenMod 12 ROM build on the Samsung Galaxy S3 Neo GT-I9300I:

Step No 1:- First, download the Android 5.0.2 CyanogenMod 12 ROM (cm-12-20141227-UNOFFICIAL-s3ve3g.zip) and Gapps on the desktop of your PC.

Step No 2:- Now plug your Galaxy Neo 3 to the PC using its USB data cable and mount USB memory.

Step No 3:- Copy the downloaded .zip files to the root folder of your microSD card of the phone.

Step No 4:- Disconnect the device from the PC after moving the .zip file to Galaxy S3 Neo.

Step No 5:- Switch Off the phone to boot it into Recovery Mode.

Step No 6:- Switch On the S3 Neo while pressing and holding Volume Up + Home + Power buttons at the same time.

Step No 7:- While your device is in Recovery Mode, take a Nandroid backup.

Step No 8:- Perform a full data wipe by choosing Wipe Data/ Factory Reset and also perform a cache wipe by selecting wipe cache partition.

Step No 9:- Now perform a wipe of dalvik cache as well.

Recovery > Advanced > wipe dalvik cache

Step No 10:- Go back to the main menu of  recovery and choose install zip from sdcard > choose zip from sdcard. Find the CyanogenMod ROM that you have already copied to the root folder of your SD Card and select it.

Step No 11:- Flash the Google Apps (Gapps) by repeating the above two steps, once the ROM is installed.

Step No 12:- Navigate to the custom recovery screen after the installation process completed successfully and reboot your S3 Neo by selecting reboot system now.

Done! Your Galaxy S3 Neo should running now CyanogenMod 12 custom build based on the latest Android Lollipop 5.0.2.


  • Perform wipe cache partition + wipe dalvik cache for a few times before rebooting the device if your device gets stuck on the booting animation or facing boot loop issue after flashing the ROM.
  • As we’ve already mentioned that one of its minor bug “Audio in calls on 2nd SIM (GT-I9300I)” then you can easily disable the second SIM on your S3 Neo by adding the following lines to /system/build.prop:
    • persist.dsds.enabled=false
    • persist.radio.multisim.config=none

Share your experience with us and let us know in the comments section below if you have any query or problem regarding flashing the highly functional unofficial CyanogenMod 12 ROM build on the Samsung Galaxy S3 Neo GT-I9300I.


  1. Reply ametishJan 14, 2015 at 9:15 am

    i have install cm 12 in s3 neo I9300I but there is problem in camera 2nd sim, sensor, screenshot any many others.please solve this bugs

  2. Reply ShobhitJan 15, 2015 at 4:30 pm

    no audio in 2nd sim….please fix it

  3. Reply Hammoud AbbasJan 26, 2015 at 10:34 pm

    i have flashed it but when i reboot to system its booting to download mode automatically help me pleas

  4. Reply Venkat TaknevFeb 26, 2015 at 4:31 pm

    Really working superb. thanks for your ROM. But the problem is no audio in sim1, (sim2 working fine in my i9300i samsung s3 neo). need your support for fix this. please!!!!!

  5. Reply Venkat TaknevFeb 26, 2015 at 4:58 pm

    also for updated stable version

    Version Information
    Status: Stable
    Current Stable Version: cm-12-20150222
    Stable Release Date: 2015-02-22

    Created 2014-12-24
    Last Updated 2015-02-23


  6. Reply sanjan kumarMar 10, 2015 at 5:01 am

    It really sucks 2nd sim voice calling problem…fix it as quick as possible…and add quick boot option and sometimes recent apps doesn’t show….

  7. Reply Ramprakash kumarMar 29, 2015 at 11:56 am

    i have install cm12 for samsung galaxy s3 neo there is proublem in camera and second sim

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