The hacker community has found many workarounds, most of which are disallowed by Apple and make it difficult or impossible to obtain warranty service.[333] "Jailbreaking" allows users to install apps not available on the App Store or modify basic functionality. SIM unlocking allows the iPhone to be used on a different carrier's network.[334] However, in the United States, Apple cannot void an iPhone's warranty unless it can show that a problem or component failure is linked to the installation or placement of an after-market item such as unauthorized applications, because of the Federal Trade Commission's Magnuson-Moss Warranty Act of 1975.[335]