Americans hoping to hack their mobile handsets may soon have help in the form of legal shelter.

The Electronic Frontier Foundation (EFF) is pressing lawmakers to amend the Digital Millennium Copyright Act (DMCA) to provide protection for users who wish to change built-in carrier settings or software locks on their phones.

Commonly known as 'jail-breaking', the process involves removing hardware or software protections that limit the handset to a single carrier or software service. The practice received widespread attention when thousands of iPhone users performed the procedure on their handsets.

The EFF is hoping to add an exemption to the DMCA, which currently forbids users from manipulating or otherwise circumventing components that protect copyright.

EFF attorney Fred von Lohmann offered the Apple handset as one specific example of the problem.

"Apple locks its iPhone to AT&T [in the US] and prevents users from installing any software that has not been pre-approved by Apple," he explained.

"Consumers need a DMCA exemption to lift the cloud of legal risk that otherwise serves only to reduce competition and consumer choice."

Apple, for its part, has already stated that it will not deliberately pursue or sabotage handsets that have been modified.

However, the EFF feels that the industry as a whole should be prevented from going after users who wish to tinker with their own devices. To further the cause, the group has set up a Free Your Phone online petition where users can show their support for the initiative.

"Companies are using the DMCA to threaten customers out of exercising their consumer rights," said Jennifer Granick, civil liberties director for the EFF.

"The Copyright Office needs to hear real stories about how these software locks frustrate consumers and developers."