I've just bought this MHL cable:
The problem is that it works perfect on my new Samsung Galaxy Tab Pro 10.1 (even without extra power supply, so it is 11 pins MHL 2.0), but it doesn't wotk on my S4 (i9500, last stock KK rom, custom recovery and rooted).
Do I need to activate any extra setting on the S4? I know it is not a samsung MHL cable, but is it possible that same MHL cable works fine on one device but it doesn't on a different device even for the same brand (Samsung)?????