retained

I've got iphone 3g 8gb from vodafone store. Would jailbreaking the phone void the warranty..?? It was on some site that if i revert back to official firmware then warranty would be retained. Also is there any other way of installing third party applications

Hey frnds I hve lost my PIN no of SBI ATM debit card. The ifficials in my city said that it cant be retained :cry: but in case of Bank Of Punjab they have retained me the pin of their ATM card. Being same Mastreo card is that possible that of one it can be retained and for other it is not...