The U.S. Court of Appeals for the Fifth Circuit has partially upheld a National Labor Relations Board ruling that workplace rules by cellphone carriers T-Mobile and MetroPCS banning photography or recording on corporate premises illegally restricts its employees from exercising their right to unionize.

The NLRB brought a complaint against the affiliated cellphone companies in 2014 after the Communication Workers of America alleged that four provisions in its corporate employee handbooks violated the National Labor Relations Act.