UNLOCKING A PHONE

[Anonymous]

I have a Galaxy S2 that I bought from O2 a couple of years ago and used with an O2 SIM.  When I upgraded to S4 I retained the S2 which I now use with a Giffgaff SIM as a backup device for emergency use.  Is it possible to have the S2 phone unlocked?  If so, do I apply to O2 or to Giffgaff, or is there some other way to achieve the desired result?

[MI5 · Accepted solution]

It has to be done by O2.
Details here http://community.o2.co.uk/t5/Other-Products-Services/Unlocking-an-O2-phone-to-use-a-different-SIM-ca...
If you used the same number it should still go through OK, if not put your S4 sim back in for a day and it should be OK.

[L_W_Ward]

The correct link is above. Just remember your security details and hope it works. In the end I called them up as it kept rejecting my details dispite having the security details correct. 

[Anonymous]

Many thanks @MI5  and @L_W_Ward