The U.S. Government Accountability Office on Tuesday upheld a protest by Harris Corp filed against the FBI's plans to award a sole-source contract to rival Motorola Solutions Inc for two-way radios under a larger umbrella contract. The congressional agency said the FBI violated federal regulations when it notified vendors that it planned to award two contracts worth $335 million to Motorola, shutting out four other companies that were authorized to supply equipment under a bigger contract with the Department of Homeland Security.