Why not just flash a stock rooted rom, and go from there. If it's the GPE there is a rooted ROM that fits that phone. That's what I did.
That's the ROM I used.
Nevermind I noticed that you have the I9505 and not the I9505G.
Are you sure I can?
"WARNING: Stop asking if you can flash this on other phones. You can NOT. It is meant for the I9505G ONLY. This is NOT a "rom". This is a system image for the I9505G. Flashing to any other phone will brick it."