TWRP keeps getting reverted to stock recovery

[Halifax]

I'm using Odin to install TWRP to my unrooted T-Mobile S5. It installs successfully and I can boot into TWRP. I even did a successful backup of the stock ROM, but as soon as I boot into the system it restores the original recovery and TWRP is gone.

I thought booting into TWRP before booting into the system would keep that from happening. Everything I read said it would patch the system on the first TWRP boot to stop the system from doing that. What am I missing? Do I have to install a custom ROM before booting back in to the system? I am looking to get Cyanogenmod installed anyway.

Would it be more reliable to write the recovery directly via ADB? Will that even work if I'm not rooted?

 

[Halifax]

Found it. I had to install SuperSu to keep that from happening. TWRP didn't even try to patch it like their website said it should.

 

[ironass]

If you are on Android 5.1.1, that will have caused your issues. Make sure that the version of SuperSU that you install is SuperSU v2.68