The talented individuals have created a means of once again removing the iPhone's dependence upon Apple's exclusive cellular carrier, AT&T, by enabling the device to work with any SIM card -- the small storage medium that retains all the data of a particular wireless subscriber. The latest unlocking method comes after slew of curious iPhone owners set out to obtain read and write file access to the devices, while some reached a further goal of unlocking the handset for use with non-AT&T cellular service. In late September, Apple issued a warning to iPhone owners about unlocking their phones and then released an update that removed filesystem access and disabled most hacked devices, effectively 'bricking' affected iPhones or rendering them useless.