PIN code required after 7.8 update

[frozen27]

Hello, I just updated my Nokia Lumia 800 to WP 7.8 with 1750.823.8858.12460 firmware, variant RM-801 VAR EURO1 GB CV MCYAN (059M539) using Nokia Care Suite.
It has been installed without any problems but when I turned the mobile on it asks me for PIN code and then for PUK code.
I am on O2 pay & go. I was trying to solve this problem with someone from o2 customer service, he was sure that he's giving me the right code but it was not working.
When I try to put this micro sim card to the other mobile, then it works and different phones does not require any codes. It is something wrong with my lumia 800 after that update.

What to do now?

 

[Lumis90]

Reset phone maybe? From settings > about

 

[frozen27]

It will not help... Phone says: This SIM card can only be used on specific networks. Contact your customer service centre for the unlock code.

I did flash the mobile with 3 different wp 7.8 firmwares.

 

[inteller]

your phone must have flashed with a locked ROM.

 

[frozen27]

I just came back to wp 7.5 using Nokia Care Suite and still can't connect to network. Still asking for PIN code. It looks like phone is blocked

 

[Lumis90]

My phone was bought in Poland, from Orange network, and when I bought it from some person it was factory unlocked I think the way iPhones is unlocked(via ebay or operators) so you can do this too. They cost 20 pounds I think.

 

[frozen27]

simlock? how? phone was factory unlocked and I did use it in several networks

 

[Pawel Bujna]

Did You solve it?

 

[jessecabrera]

My Dad's Android had this problem. I used another phone to call my service provider which was T-mobile and asked for my dads PUK code. I put the code in and then it asked me to make a new one so I put a 4 digit code I could remember. Then, I went to the phone's settings and disabled the option for the phone to always ask for the PUK code everytime I turned the phone on. I don't know if it's the same for Windows Phone, but I hope it helps.