Citing from the official Gionee website that the device will not receive any Android Marshmallow versions, therefore the existence of CM13 here will heal your disappointment.
The credit should be given to Arun Chaudhary, as the Gionee Marathon M3 developer, who have worked so well delivering the ROM that's based on CyanogenMod ROM for us to use.
The ROM is reported to work and run almost with less issues, most of the main features work, still it's not a 100% perfect. However you are welcomed and invited to flash it on your device. And prove yourself whether this ROM deserves to be your daily driver or not.
If you are interested, then read on to the following preconditions, afterward step to the instructions.
- This non-official CM13 ROM is based on AOSP source, that means you have to firstly unlock your device's bootloader.
- Flashing this ROM requires a root access and then a custom recovery installed, on this post I use a CWM recovery.
- There is no Gapps on this ROM, therefore you will need to install the Google apps separately.
- Make backups for every data you consider so important to keep.
- Please to perform each step on the instructions section without skipping anything.
- ROM OS Version: 6.0.1 Marshmallow.
- ROM Kernel: Linux 3.4.x.
- ROM Firmware Required: KitKat Stock.
- Based On: CyanogenMod 13.
How to install unofficial CM13 Android 6.0.1 Marshmallow ROM on Gionee Marathon M3.
- Move all the zip files you previously stored on PC to your Gionee M3 using the USB transferring cable.
- Once done, just turn off your device to enter to the CWM recovery mode.
- When you are in the CWM recovery, now you may select the Wipe Data/Factory Reset.
- Now just select the Wipe Cache Partition. Continue your move by performing the Wipe Dalvik Cache.
- You must now select the Install Zip From SD Card -> Choose Zip From SD Card
- The flashing process take place now, just wait till it's complete, when it is just select the *****Go Back***** -> Reboot System Now. To restart your Android device. Again just wait.
- Rebooting will take place, it takes sometimes, because your device's loading new ROMs and Gapps.