Invalid SIM Problem on a iPhone 4 (o2) PLZ HELP

[gspeedy]

I got a iPhone 4 from a market stall in Liverpool for £220, it come with a PAYG o2 SIM card, that SIM works good.

I want to put in my o2 PAYG SIM card, but i get a message saying "Invalid SIM"

I went to a local o2 shop & told them about my o2 sim card not working.
The guy got me a new blank SIM & transferred my number on it.

But am still getting same message saying "Invalid SIM"

[gspeedy]

Ive tested my o2 SIM card in my blackberry and it works fine. really can't understand why its not working in this iPhone.

[firestorm]

Now i ve stopped giggling at some one buying a phone of market stall in Liverpool
Is it jailbroke?Do you know what firmware is on it even better do you know which baseband?
If its jailbroke you could try ultrasnow from cydia that should unlock it to any sim.If it is the latest baseband then you can not unlock with ultrasnow.

[gspeedy]

yep. i have jailbroke 5.1.1 (9b206)fw & bb: 04.12.01

[gspeedy]

Am being told by 02 that the sim might need activating.. just tried syncing with itunes but the activate screen didn't come up.
Is the any other way to activate it?

[gspeedy]

i downloaded ultrasnow and installed it but i don't know how to run it after re-spring.

[firestorm]

Sorry but bb: 04.12.01 is unlock able, if the phone was a contract sim to o2 then it may be possible it is locked to o2 contract sim only not sure though.You could always try a restore on itunes but you will lose your jailbreak you should be able to jailbreak again it with redsnow.BUT it may ask you at the end of the restore for a valid sim before its activated,so you could end up stuck.

[gspeedy]

Think your right.. only thing is that the card i got with the phone is PAYG on contact..
Am restoring with my o2 SIM card in to see if it will activate..

[firestorm]

Good luck
let us know how you get on
ultra snow just runs in the back ground once resprung it should take effect when your phone reboots.

[gspeedy]

a restore with my o2 SIM in worked. thanks for you help.