How ToROMs

How To Flash Pre-Rooted Marshmallow Firmware on Galaxy S5 (T-Mobile)

The latest Android Marshmallow firmware is available for the Galaxy S5 G900T (T-Mobile). This update comes with important stability improvements, security patches and bug fixes. It can be considered a stable and smooth Android M system. Everyone wish to get and use the new Android OS version but this is also true that root access gets revoked after installing official Android updates. So if your T-Mobile Samsung Galaxy S5 is running on the official Android Marshmallow firmware and want to regain root access on your phone then we have a step-by-step guide given below. But keep in mind that you can only install this pre-rooted OS on your T-Mobile Galaxy S5 if its already rooted and the latest version of a custom recovery like TWRP recovery is already installed. It is recommended to downgrade and gain root access and follow these instructions to update back to Android Marshmallow.

Thanks to senior XDA member muniz_ri for providing this customized and optimized ROM. In this guide we’ll use a pre-rooted firmware and ll not use the SuperSU root exploit. This pre-rooted firmware is exactly the same as the stock Android M software released by T-Mobile. Hence, you will keep everything safe while ensuring root again as well as its cleaned up and unlocked so there are no bloatware or any other built-in app to slow down your Galaxy S5. Since a pre-rooted ROM will be flashed, so you will need Odin flashing tool to complete this guide. Odin is an official tool which is originally developed by Samsung, especially used for update-types of operations but here it will perfectly work on root purpose also.

Update Galaxy S5 (T-Mobile) to Pre-Rooted Marshmallow Firmware


This guide containing the Rooted Marshmallow firmware and instructions can be used only with the Galaxy S5 G900T. Do not try to install this firmware on any other device or incorrect variant. Verify the model number of your device before proceeding to the installation guide.


AndroidBlog will not be held liable for any kind of damage occurred to your Samsung Galaxy S5 during or after the installation of Pre-Rooted Marshmallow OS. Proceed at your own risk.


  • Make a proper backup of all the existing data and settings of your Galaxy S5, in case anything goes wrong then you’ll be able to restore your data back.
  • Verify that you’ve properly installed the Galaxy S5 USB Drivers on the PC.
  • Enable USB Debugging Mode on your S5 by navigate to Settings > Developer Options > check the USB Debugging option.
  • The latest custom recovery like TWRP should be installed on your S5.
  • The Galaxy S5 should be already rooted.
  • Check the battery level of your S5, it should be charged at least about 80% before proceeding to the installation guide.

Required Files:

Steps to Install Rooted Marshmallow OS on the T-Mobile Galaxy S5:

Step No 1:– First, download the Rooted Android Marshmallow ( and Odin v3.10.7 for Galaxy S5 on the desktop of your PC and extract the .zip files.

Step No 2:– Turn OFF your Galaxy S5 in order to boot into Download Mode.

Step No 3:– Turn the device ON by pressing and holding the Volume Down + Home keys at the same time and then press the Power button till the construction Android robot and a triangle appear. Now press Power button once again to confirm to enter into Download Mode.

Step No 4:– Launch Odin tool on your PC as an Administrator and plug your phone to your PC while your phone is in the Download Mode.

Step No 5:– One of the ID:COM boxes will turn yellow with the COM port number once the phone is connected successfully.

Step No 6:– Select the firmware files that you want to flash on your Galaxy S5. (Already extracted in Step No 1)

Click on ‘AP’ and select file with ‘AP’ in its name.

Click on ‘CP’ and select file with ‘MODEM’ in its name. Ignore this step if there is no such file.

Click on ‘CSC’ and select file with ‘CSC’ in its name. Ignore this step if there is no such file.

Click on ‘PIT’ and select the .pit file. Ignore this step if there is no such file.

Click on ‘BL’ and select file with ‘BL’ in it’s name. Ignore if there is no such file.

Step No 7:– In Odin, make sure that the Auto Reboot and F. Reset Time options are ticked but the Re-Partition option should be unchecked.

Step No 8:– Click on the Start button in Odin to initiate the installation process. It will take a few minutes to complete.

9:– Once the installation process is successfully finished, the Galaxy S5 will restart. Unplug the phone after you see the home screen.


If you face a boot loop issue after installing the firmware then go back to recovery and hard reset your T-Mobile Galaxy S5 and to clear app data cache.

Recovery -> select “wipe data factory reset” -> “wipe cache partition”.

Done! You have successfully installed a pre rooted Android Marshmallow firmware on T-Mobile Galaxy S5.

Aamir Jamal

An Android Geek and audiophile who love to read and write reviews/tutorials about gadgets and new tech stuff. He has written 1007 guides and other posts.

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button