Can you try following boot image ?
	ftp://ftp.sra.co.jp/pub/os/NetBSD/misc/arc/openbsd.nec.gz
This is kernel for RISCstation, and configured to use serial console, 
so please connect COM0 to other machine's terminal port and watch it.
(Baudrate may be 19200bps, but may vary)
--
soda