I've put my giffgaff sim in an unlocked galaxy phone, the phone recognises the sim and displays o2-uk/GiffGaff on the home screen, however i have no network signal at all, i've chnaged all the apn settings etc and stil nothing, any help would be appreciated.
The sim has to be fully activated with a £10 top up before it will work properly.
If it is already fully activated you may need to delete all the existings APN's on the Galaxy and then restart the phone....Then text SETTINGS to 2020....or....re-enter the APN details manually
Take a look at these guides they may help....
http://bit.ly/giffgaffactivate - Complete guide to activation
http://bit.ly/giffgaffandroid - Android guide
http://bit.ly/giffgaffAPN - Definitive APN Settings
http://bit.ly/giffgaffgfc - Buying a goodybag from existing credit