AOSP is one of the most popular custom firmwares especially for the fact that it has a similar stock Android look and feel. Bringing stability and improved performance and being your only chance to enjoy Android 6.0 Marshmallow on Galaxy S3 I9300, don’t hesitate to keep reading what I’ve prepared for you.
Don’t be disappointed by the fact that I don’t get you right to the flashing procedure. As it happens with all the custom ROMs, this is not eiher an official release by Samsung, but nothing more than a custom ROM which requires a custom recovery like ClockworkMod to flash the ROM zip file on your phone and a rooted device. After all, without root you cannot install a custom ROM, so there is no way to run Android 6.0 Marshmallow on your Samsung Galaxy S3.
Then, my advice is to create a backup of all the important data that you have stored in your Galaxy S3 device, especially as long as this is a custom ROM. So, if the Android 6.0 M ROM will run with bugs and if you experience any other severe issues, it is up to you to go back to stock and solve all of them.
Download and install USB drivers for Samsung Galaxy S3 in your computer and as I always tell you, don’t forget to enable USB debugging option by pressing Menu > Settings > Applications. Then, navigate and tap on Developer Options to make sure that the USB Debugging option is indeed enabled.
Ensure that your Samsung Galaxy S3 I9300 carries more than 60% of charge. If not, do not forget to plug in the charger before flashing the Android 6.0 Marshmallow OS as long as your phone might get bricked if it gets turned off during the update process.
At the end, let me remind you that the below tutorial is compatible only with the Samsung Galaxy S3 model number of I9300, so don’t apply these steps if you have another model or Android based smartphone and don’t forget about the risks coming along with the Android 6.0 features. There might be some issues with the ROM, so I cannot guarantee that it is safe enough for your handset; furthermore, such a procedure is risky and any mistake could lead to damaging the phone.
How to Flash AOSP Android 6.0 Marshmallow on Galaxy S3 I9300:
- The Android 6.0 Marshmallow firmware is waiting to be downloaded from here;
- Also take Google apps and the boot image by using this link;
- Connect your Galaxy Note 3 with the computer via the USB cable;
- It’s time to copy/paste both files on your device;
- Disconnect the USB cable;
Turn off the handset right away;
- Boot into custom recovery mode, so press and hold Volume Up, Down and the Power buttons simultaneously until the Samsung logo shows up. Leave the keys for and then, hold them again. Use Volume keys to scroll and the Power button to select;
- From recovery, you have to make the usual wipe, so select “wipe data factory reset”, followed by “wipe cache partition” and “wipe dalvik cache”;
- Locate the CM 13 firmware file copied earlier and select it;
- Tap on yes to confirm installation and wait for the ROM installation to be completed;
- Also install the Google Apps package too by using the same steps as for the firmware file;
- Then, you have to return to main recovery menu now and select reboot system now to boot up into the latest Android 6.0 Marshmallow.
Starting to this moment, enjoy an unofficial, yet pure Android M experience on your own Samsung Galaxy S3 I9300 handset!