I have that issue, too.
Serial control port /dev/ttyS0 works in Foonas-EM, but not in davy gravy's kernel 220.127.116.11 or in ramp's kernel 18.104.22.168. On some kernels, echoing the special codes to the serial port has no effect.
The shutdown sequence for halting would probably work out better (currently does not power off).
According to 'fuser', avr-evtd attaches to /dev/ttyS1, but 'echoing' to that device produces an error.
'setserial -g' reports
/dev/ttyS0, UART: 16550A, Port: 0x0000, IRQ: 104
/dev/ttyS1, UART: unknown, Port: 0x0000, IRQ: 0
I am not sure how the daemon does its job, anyway. I cannot recall the device rebooting itself except under openlink in 2006.