TMS570LC4357: Writes to IOMM KICKER0 & KICKER1 has no effect

Part Number:TMS570LC4357

Hello everyone, 

I'am trying to pinmux EMIF pins but I can't write to KICK registers to unlock pinmuxing. Is there something I need to setup prior to be able to modify the value of these registers? 

I'am pretty sure Iam missing something obvious but I can't figure it out. 

Thanks in advance.