Well yeah it happened when I flashed some deodex packages.
I tried almost every single way I could find in the internet and I concluded my motherboard got damaged.
WiFi works fine even at current state, just the IMEI, IMEI SV, Baseband are screwed. (See my thread in
XDA forum about this)
I had been flashing my phone almost every few days or week (for 3 months+) without problem until that day, plus forgetting to backup my /efs folder
I also read that there is no flash counter in our SL devices.
Just one question, if I were to do as you said, how much would they (Samsung SC) charge for cases like this without warranty?
This sounds like a real motherboard problem. But I might be wrong.

I read that many i9003 motherboards are damaged within a year or so. People even recommend to find some reasons to get Samsung to change your motherboard before warranty ends. But then again, I might be wrong.

You nee to act dumb, if your phone is still under warranty then they shouldn't charge you anything for it because this is not consider as accidental damage.
There is flash counter in SL as well if not mistaken, same goes to almost all Galaxy phones.