I have a rooted Galaxy S6 on 5.1.1, the first and only version I rooted my device on. I want to update to Marshmallow and still have a rooted phone. What are the steps I need to do to make this happen?
Updating your Samsung smartphone to a stock firmware
Most Samsung smartphones can be flashed with the Odin Tool. But before you can flash you have to get your devices model number, a compatible firmware, the USB Drivers and Odin.
- Get your model number: Visit your settings menue - navigate to "About Phone" and see if you can find your model-number. See here for typical model-numbers of a Galaxy S5.
- Enter your model number on sammobile and download the most up-to-date firmware. If there is one for your region then take that - if there is no update available for your region you can flash other regions aswell. (If you are experiencing problems with connectivity, flash another modem)
- Make sure you have the Samsung USB Drivers for Windows installed
- Follow the steps on the download page of your firmware:
Extract (unzip) the firmware file Download Odin v3.10.7 Extract Odin ZIP file Open Odin v3.10.7 Reboot Phone in Download Mode (press and hold Home + Power + Volume Down buttons) Connect phone and wait until you get a blue sign in Odin Add the firmware file to AP / PDA Make sure re-partition is NOT ticked Click the start button, sit back and wait few minutes
This process works for rooted aswell as unrooted samsung phones. Your phone will be running an unrooted (stock) firmware after this process.
To root your phone again - visit Chainfire's site and select the appropriate package for your device-model. Then extract this file and flash it like the other package. (Start Odin, select the .tar.md5 file into the AP/PDA slot of Odin and start)
Use a custom ROM
You can also use a custom ROM to update your phone to a newer android version. You'll need to install a custom recovery (like TWRP) and download an appropriate ROM zip.
Download Odin v3.10.7 Extract Odin ZIP file Open Odin v3.10.7 Reboot Phone in Download Mode (press and hold Home + Power + Volume Down buttons) Connect phone and wait until you get a blue sign in Odin Add the TWRP Image(https://twrp.me/devices/samsunggalaxys6.html)(twrp-3.0.2-0-zeroflte.img.tar) to the AP-Sector of Odin Make sure re-partition is NOT ticked - disable the Option "Auto-Reboot" Click the start button, sit back and wait few seconds
When it is done (Odin shows the "PASS" message) - press and hold the Volume Up+ Power Button on your device until it restarts - release the power button as soon as see the boot-up screen. If you want to install ROMs - visit XDA-Developers and look into the Android Development section.
If you have downloaded a ROM zip, copy it to your device, boot into TWRP and wipe /system, /cache, /dalvic. Flash your zip file with TWRP and boot up to the new ROM :)
Sources and further reading: Root Samsung Galaxy S6 and Install TWRP Recovery (All Models)
Warning: This process will very likely trigger the KNOX fuse and you're going to loose warranty in most regions.
So long as you don't try an OTA (Over The Air update, such as you would be offered with a stock phone), you shouldn't lose root. You just need to choose and flash a new ROM. There are many ROMs you could choose from but I always used Cyanogen Mod on my rooted phones. CM has it's own updater, so you can update with this in future.
Google your options and make sure you follow instructions carefully. With many ROM's you will need to install the Google Store app manually if you want to install apps in the normal way after your update.