The CyanogenMod developers have launched the CyanogenMod 13 ROM for the devices’ Android Marshmallow update. The ROM is still at its experimental stages thus may feature a few issues to be fixed in upcoming CM13 firmware updates.NOTE: Installation of custom ROMs and rooting devices may void the warranty on the device.This custom ROM is compatible with all Galaxy S5 models (codenames: klte, klteacg, kltedcm, klteub, klteatt, kltecan, and kltetmo) and any attempt on another variant may brick the device.
- Install the current version of TWRP recovery to back up all the data on the device.
- Confirm that the right USB drivers are installed on the PC for an easy unpacking of the ROM and Google Apps to the Galaxy S5’s storage.
- The next step is to download CM13 Android 6.0 Android Marshmallow custom ROM and Marshmallow Google Apps.
- Connect the S5 to the PC and copy the Android Marshmallow ROM zip file to the device’s internal memory.
- Turn off the Galaxy S5 then reboot it to TWRP Recovery by long-pressing the Power and Volume down keys together till you see a TWRP logo on the screen.
- Next a Nandroid backup should be done, by simply selecting the backup option on TWRP.
- After the backup completion, in the TWRP menu, select the wipe option then Advanced Wipe. Tap on all the options then begin the wipe process.
- Choose the install option in the main menu of TWRP. Navigate to the location of the saved ROM zip file, select it and confirm installation.
- Repeat the previous step for Google Apps installation.