Default Plz help me!

I am on Stock Asia ROM:

System Version: 973.94.328.XT910.Asiaretail.en.03

Android: 4.0.4

Can someone please guide me how do I get to the official JB update?

The problem is, I am GSM and the update is apparently only CDMA

I am rooted

I tried flashing EU FW but nothing happened..some Status 6 error in the file.

Funny part is, I HAD installed JB a couple of years back when it had come, but now I have completely forgotten the procedure.

I even have all the files of that time..

Can someone just show me the way out of GSM>CDMA and then back?