You have to get MAIN firmware with CID53,(I've ever done this)
I didn't want update with SEUS again..huh..

Or to back ur CID into 52, u can use simoxs romp patcher(I don't know how to use)
Sorry, I just know from someone's post,
here ìs the link to the thread
CID 53 to 52 - Top Sony Forums

I hope it can help...