I am running on an i.MX6 the picoserver app https://github.com/seL4/camkes/tree/master/apps/picoserver Both the echo and listener components print out to serial: listener instance starting up, going to be listening on 10.0.0.2:4321 echo instance starting up, going to be listening on 10.0.0.2:1234 but only the echo component receives PicoTCP events: Assigned ipv4 10.0.0.2 to device eth0 IPv6: DAD verified valid address. echo: Connection established with 10.0.0.1 on socket 1 echo: Received a message on socket 3, going to echo to Listener echo: Received a message on socket 3, going to echo to Listener echo: Received a message on socket 3, going to echo to Listener Note that the listener component does not even print out "Connection established". I tried to figure out why, and found out that by editing this part of picoserver.camkes: /* * The attributes of the *_(control/send/recv) interfaces should be the same and unique between * different components, this determines the client ID of this component with respect to * the PicoServer component */ echo.echo_control_attributes = "1"; echo.echo_recv_attributes = "1"; echo.echo_recv_shmem_size = 0x1000; echo.echo_send_attributes = "1"; echo.echo_send_shmem_size = 0x1000; echo.ip_addr = PICOSERVER_IP_ADDR; /* * Listener config */ listener.listener_control_attributes = "2"; listener.listener_recv_attributes = "2"; listener.listener_recv_shmem_size = 0x1000; listener.listener_send_attributes = "2"; listener.listener_send_shmem_size = 0x1000; listener.ip_addr = PICOSERVER_IP_ADDR; and changing the attributes to this: /* * The attributes of the *_(control/send/recv) interfaces should be the same and unique between * different components, this determines the client ID of this component with respect to * the PicoServer component */ echo.echo_control_attributes = "0"; echo.echo_recv_attributes = "0"; echo.echo_recv_shmem_size = 0x1000; echo.echo_send_attributes = "0"; echo.echo_send_shmem_size = 0x1000; echo.ip_addr = PICOSERVER_IP_ADDR; /* * Listener config */ listener.listener_control_attributes = "1"; listener.listener_recv_attributes = "1"; listener.listener_recv_shmem_size = 0x1000; listener.listener_send_attributes = "1"; listener.listener_send_shmem_size = 0x1000; listener.ip_addr = PICOSERVER_IP_ADDR; then listener will print that it has connected to echo, but now echo will not print out anything. How do I make both echo and listener print out on the serial port? Which part of the code looks at echo.echo_recv_attributes = "1"; and listener.listener_recv_attributes = "2"; in order to determine the client ID of the echo and listener components with respect the PicoServer component? From what I can tell, attributes was not declared as an actual attribute.