So I have rooted my S4 i9505 and want to install a custom rom, but when I boot my phone and hold Power, Volume Up and Home button it takes me to the Samsung recovery, I have since seen different guide and realised I should have rooted via a PC and Odin, do I have to unroot to root again via Odin? Or is there a way to install a custom rom with the current state my phone is at?