This document contains the first Amendment to revised ITU-T Recommendation G.984.3 (03/2008) "GPON: Transmission convergence layer specification". This Amendment: - specifies the ONU Registration method; - clarifies the definitions of Dying_Gasp and Deactivate_ONU-ID PLOAM messages; -reconciles the description of PON alarms; -adds a new Appendix clause addressing transmission of MPLS datagram using GPON Encapsulation Method; -provides necessary clarifications to several standard items, including the use of the DBA reference model, the required number of supported reassembly buffers, and details of the key exchange.