Samsung Galaxy Note 3 did get through Lollipop update just couple of months back and it might not be included in the official Samsung Marshmallow update. Unofficially you can use the CM13 Custom ROM to update the device to Android Marshmallow. This custom ROM has all the features of the original Android Marshmallow update. You can also wait for the official update to be available or go this way.
If you are anxious of updating your Samsung Galaxy Note 3 to Android 6.0 Marshmallow, then here is an unofficial way of doing that.The CM13 ROM is unofficial but it has all the features of Android Marshmallow official update.This CM13 ROM work well and it does not have any faults.
This CM13 ROM works with all variants of the Samsung Galaxy Note 3 that includes the AT&T Note 3 N900A, T-Mobile Note 3 N900T and other GSM variants of Note 3 like N900F and others.
Preparing Your Phone
- Device should be fully charged up to 100%.
- Backup all the important data to some external storage.
- USB drivers for device should be installed on the PC.
- Make a Nandroid backup of the current ROM in case the new version does not work properly you can restore it.
- Custom recovery like TWRP must be installed on the device.
- Device should be rooted and its bootloader must be unlocked.
- USB debugging mode should be enabled on the device. Go to Settings > Developer options > USB debugging mode.
Install CM13 Android Marshmallow based custom ROM on Samsung Galaxy Note 3:
- Download the Android Marshmallow AOSP file from here.
- Download the Android Marshmallow Gapps file from here.
- Transfer the Files to Device internal or external storage where it will be easy to locate.
- Turn off the device and reboot it into Recovery mode by using appropriate hardware buttons.
- In recovery select Wipe option and then tick the Data, Cache, Dalvik Cache from the next page.
- Swipe the Swipe to wipe button at bottom of the Screen.
- Now return to main menu and select the Install options.
- Navigate to the ROM zip file and select it, then swipe the button at bottom to flash it.
- In the same way flash the Gapps file.
- Return to main menu and select the Reboot option to reboot the device.
Your device will now be updated to Android Marshmallow, you can check the version of Android in Settings > About device.