Apply by doing:
        cd /usr/src
        patch -p0 < 019_nsphy.patch

And then rebuild your kernel.

Index: sys/dev/mii/nsphy.c
===================================================================
RCS file: /cvs/src/sys/dev/mii/nsphy.c,v
retrieving revision 1.6
diff -u -r1.6 nsphy.c
--- sys/dev/mii/nsphy.c	1999/07/23 12:39:11	1.6
+++ sys/dev/mii/nsphy.c	2000/01/20 14:22:31
@@ -243,7 +243,6 @@
 
 		switch (IFM_SUBTYPE(ife->ifm_media)) {
 		case IFM_AUTO:
-			nsphy_reset(sc);
 			/*
 			 * If we're already in auto mode, just return.
 			 */