CM13 ROM unofficial, for Samsung Galaxy S4 is now out. This custom ROM will update your device to Android Marshmallow. So, if you are anxious of Updating your Samsung Galaxy S4 from Android Lollipop to Android Marshmallow, then here is an unofficial way of doing that.Samsung Galaxy S4 GT-I9500

The CM13 ROM is unofficial but it has all the features of Android Marshmallow official update.This CM13 ROM work with the following Samsung Galaxy S4 variants (GT-i9505, GT-i9500, GT-i9505 and GT-i9505G). If you are using any of this S4 model, then you will be able to install Android Marshmallow on it using a this custom CM13 ROM.

Preparing your Samsung Galaxy S4:

  • Device should be fully charged upto 100%.
  • Backup all the important data to some external storage.
  • USB drivers  for Samsung Galaxy S4 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.USB Debugging

Install Android Marshmallow based CM13 ROM:

  1. Download the Android Marshmallow CM13 file to be available soon.
  2. Download the Android Marshmallow Gapps file from here.
  3. Transfer the Files to Device internal or external storage.
  4. Turn off the device and reboot it into Recovery mode by using appropriate hardware buttons.
  5. In recovery select Wipe option and then tick the Data, Cache, Dalvik Cache from the next page.
  6. Swipe the Swipe to wipe button at bottom of the Screen.
  7. Now return to main menu and select the Install options.
  8. Navigate to the CM13 ROM zip file and select it, then swipe the button at bottom to flash it.
  9. In the same way flash the Gapps file.
  10. Return to main menu and select the Reboot option to reboot the device.

Your device is now updated to Android Marshmallow with help of CM13 ROM from CyanogenMod. To check the status go to Settings > About Device.