174 bytes added ,  03:42, 5 November 2019
After the header is the associated data for size0 and size1. The functions which generate the header always leave size0 at value 0, when receiving the data for size0 the received data is unused.
The first message used by the client with SystemUpdate is ID 0x1.
| 0x0 || 0x0 || 0x0 || Tells the server to exit.
| 0x1 || SystemUpdate Meta [[NCM_services#Cmd69ContentMetaKey|ContentMetaKey]] || 0x38-bytes, unknown. byte [[CNMT#Content_Records|Content Record]] || This is Gets the first message used by Content Record for the specified ContentMetaKey. The SystemUpdateclient uses the ContentMetaKey from [[#Cmd69]].
| 0x3 || 0x10-byte input for [[ETicket_services|es]] GetCommonTicketAndCertificateSize/GetCommonTicketAndCertificateData. || 0x8-bytes: two size u32s. Then two blocks of data with the sizes specified by the u32s. The server loads the sizes and data from [[ETicket_services|es]] GetCommonTicketAndCertificateSize/GetCommonTicketAndCertificateData. || This is presumably used by the client for Application-Delivery. The two blocks of data are used as the buffers for [[ETicket_services|es]] ImportTicket by the client.