[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?

[Xkernel]

write down your IMEI，I may can help you.

[dedo619]

same thing happened to me..can any1 help me regarding this please

[A Gilani]

can you help me.
the same happened with me

[gedzum]

The PIN and PUK codes should be with the documentation that came with your SIM card. At least that's how it was for me. Something must have triggered the phone to ask for the codes after the update. You guys will most likely have to contact your service provider/carrier support.

With regards to OP, perhaps you entered the wrong codes too many times and the phone is blocked? I believe if you enter both PIN and PUK codes wrong 3 times in a row, the SIM will be blocked