diff --git a/sys/arch/macppc/include/autoconf.h b/sys/arch/macppc/include/autoconf.h
index 0c03e85a2050..dc56567e7795 100644
--- a/sys/arch/macppc/include/autoconf.h
+++ b/sys/arch/macppc/include/autoconf.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: autoconf.h,v 1.18 2011/07/01 21:02:15 dyoung Exp $	*/
+/*	$NetBSD: autoconf.h,v 1.19 2019/01/08 07:46:10 mrg Exp $	*/
 
 /*-
  * Copyright (C) 1998	Internet Research Institute, Inc.
@@ -34,7 +34,9 @@
 #ifndef _MACHINE_AUTOCONF_H_
 #define _MACHINE_AUTOCONF_H_
 
-#include <sys/bus.h>	/* for bus_space_tag_t */
+#include <sys/bus.h>
+
+#include <prop/proplib.h>
 
 struct confargs {
 	const char *ca_name;
diff --git a/sys/arch/ofppc/include/autoconf.h b/sys/arch/ofppc/include/autoconf.h
index 6be4d688f9fd..8be04aaed74a 100644
--- a/sys/arch/ofppc/include/autoconf.h
+++ b/sys/arch/ofppc/include/autoconf.h
@@ -1,10 +1,12 @@
-/*	$NetBSD: autoconf.h,v 1.15 2011/07/01 21:02:15 dyoung Exp $	*/
+/*	$NetBSD: autoconf.h,v 1.16 2019/01/08 07:46:10 mrg Exp $	*/
 
 #ifndef _OFPPC_AUTOCONF_H_
 #define _OFPPC_AUTOCONF_H_
 
 #include <sys/bus.h>
 
+#include <prop/proplib.h>
+
 struct confargs {
 	const char	*ca_name;
 	u_int		ca_node;
diff --git a/sys/arch/powerpc/include/types.h b/sys/arch/powerpc/include/types.h
index 2d6ad5851910..1dc4a962a95d 100644
--- a/sys/arch/powerpc/include/types.h
+++ b/sys/arch/powerpc/include/types.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: types.h,v 1.56 2017/01/27 17:22:39 christos Exp $	*/
+/*	$NetBSD: types.h,v 1.57 2019/01/08 07:46:11 mrg Exp $	*/
 
 /*-
  * Copyright (C) 1995 Wolfgang Solfrank.
@@ -87,6 +87,8 @@ typedef __uint32_t tlb_asid_t;		/* for booke */
 #define	__HAVE___LWP_GETTCB_FAST
 #define	__HAVE___LWP_SETTCB
 #define	__HAVE_TLS_VARIANT_I
+#define	__OPENFIRMIO_OPEN_CHECK_BROKEN
+int __openfirmio_open_check_broken(void);
 
 #if defined(_KERNEL) || defined(_KMEMUSER)
 #define	PCU_FPU		0	/* FPU */
diff --git a/sys/arch/powerpc/powerpc/openfirm.c b/sys/arch/powerpc/powerpc/openfirm.c
index 9302c9932277..65ec1ad59cdc 100644
--- a/sys/arch/powerpc/powerpc/openfirm.c
+++ b/sys/arch/powerpc/powerpc/openfirm.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: openfirm.c,v 1.26 2018/09/03 16:29:26 riastradh Exp $	*/
+/*	$NetBSD: openfirm.c,v 1.27 2019/01/08 07:46:11 mrg Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
@@ -34,7 +34,7 @@
 #include "opt_multiprocessor.h"
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: openfirm.c,v 1.26 2018/09/03 16:29:26 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: openfirm.c,v 1.27 2019/01/08 07:46:11 mrg Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -42,6 +42,7 @@ __KERNEL_RCSID(0, "$NetBSD: openfirm.c,v 1.26 2018/09/03 16:29:26 riastradh Exp
 #include <uvm/uvm_extern.h>
 
 #include <machine/psl.h>
+#include <machine/autoconf.h>
 
 #include <dev/ofw/openfirm.h>
 
@@ -757,3 +758,11 @@ ofbcopy(const void *src, void *dst, size_t len)
 	while (len-- > 0)
 		*dp++ = *sp++;
 }
+
+#ifdef __OPENFIRMIO_OPEN_CHECK_BROKEN
+int
+__openfirmio_open_check_broken(void)
+{
+	return strncmp(model_name, "Pegasos", 7) == 0 ? ENXIO : 0;
+}
+#endif
diff --git a/sys/dev/ofw/openfirmio.c b/sys/dev/ofw/openfirmio.c
index 94a9ee3824c7..d1b1d1ecdb51 100644
--- a/sys/dev/ofw/openfirmio.c
+++ b/sys/dev/ofw/openfirmio.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: openfirmio.c,v 1.13 2014/07/25 08:10:37 dholland Exp $ */
+/*	$NetBSD: openfirmio.c,v 1.14 2019/01/08 07:46:11 mrg Exp $ */
 
 /*
  * Copyright (c) 1992, 1993
@@ -41,7 +41,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: openfirmio.c,v 1.13 2014/07/25 08:10:37 dholland Exp $");
+__KERNEL_RCSID(0, "$NetBSD: openfirmio.c,v 1.14 2019/01/08 07:46:11 mrg Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -63,10 +63,11 @@ static int openfirmgetstr (int, char *, char **);
 
 void openfirmattach (int);
 
-dev_type_ioctl(openfirmioctl);
+static dev_type_open(openfirmopen);
+static dev_type_ioctl(openfirmioctl);
 
 const struct cdevsw openfirm_cdevsw = {
-	.d_open = nullopen,
+	.d_open = openfirmopen,
 	.d_close = nullclose,
 	.d_read = noread,
 	.d_write = nowrite,
@@ -117,7 +118,18 @@ openfirmgetstr(int len, char *user, char **cpp)
 	return (error);
 }
 
-int
+static int
+openfirmopen(dev_t dev, int flag, int mode, struct lwp *l)
+{
+
+#ifdef __OPENFIRMIO_OPEN_CHECK_BROKEN
+	return __openfirmio_open_check_broken();
+#else
+	return 0;
+#endif
+}
+
+static int
 openfirmioctl(dev_t dev, u_long cmd, void *data, int flags, struct lwp *l)
 {
 	struct ofiocdesc *of;