Cisco Systems has come clean about violations of the General Public Licence (GPL) in its iPhone WIP300. 

The company is "taking steps to resolve a single issue" raised by an open source researcher last week, according to a blog posting by John Earnhardt, a senior manager of Cisco's global media operations. 

Dutch open source activist Armijn Hemel claimed last week that Cisco violated the terms of the open source GPL in at least five components of its iPhone model.

The missing source code included the 'gdbserve' GNU debugger, the 'fwupg', 'flash' and 'webconfig' tools that contain code from the Memory Technology Utilities Subsystem for Linux, as well as the 'mystun' and 'phone' tools, Hemel alleged.

Earnhardt claimed, however, that Cisco violated the code in only one instance. "Cisco has thoroughly investigated the other issues raised and verified the product's compliance with GPL," he wrote.

Under the terms of the GPL, developers are required to publish the source code of any GPL software that they distribute, including changes to the original code.

Hemel first reported his findings to Cisco in October, and went public after Cisco filed a lawsuit against Apple over the iPhone trademark.

The researcher alleged that, while Cisco accused Apple of stealing a registered trademark, the company itself was guilty of intellectual property theft through the GPL violations.