diff --git a/distrib/utils/sysinst/arch/mac68k/md.c b/distrib/utils/sysinst/arch/mac68k/md.c
index 835e638cfbe0..0a1338d8540a 100644
--- a/distrib/utils/sysinst/arch/mac68k/md.c
+++ b/distrib/utils/sysinst/arch/mac68k/md.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: md.c,v 1.19 2001/01/14 02:38:19 mrg Exp $ */
+/*	$NetBSD: md.c,v 1.20 2001/07/14 07:57:16 scottr Exp $ */
 
 /*
  * Copyright 1997 Piermont Information Systems Inc.
@@ -683,7 +683,29 @@ md_pre_disklabel()
     }
     /*
      * Well, if we get here the dirty deed has been done.
+     *
+     * Now we need to force the incore disk table to get updated. This
+     * should be done by disklabel -- which is normally called right after
+     * we return -- but may be commented out for the mac68k port. We'll
+     * instead update the incore table by forcing a dummy write here. This
+     * relies on a change in the mac68k-specific writedisklabel() routine.
+     * If that change doesn't exist nothing bad happens here. If disklabel
+     * properly updates the ondisk and incore labels everything still
+     * works. Only if we fail here and if disklabel fails are we in
+     * in a state where we've updated the disk but not the incore and
+     * a reboot is necessary.
+     *
+     * First, we grab a copy of the incore label as it existed before
+     * we did anything to it. Then we invoke the "write label" ioctl to
+     * rewrite it to disk. As a result, the ondisk partition map is
+     * re-read and the incore label is reconstructed from it. If
+     * disklabel() is then called to update again, either that fails
+     * because the mac68k port doesn't support native disklabels, or it
+     * succeeds and writes out a new ondisk copy.
      */
+    ioctl(fd, DIOCGDINFO, &lp);    /* Get the current disk label */
+    ioctl(fd, DIOCWDINFO, &lp);    /* Write it out again */
+
     close (fd);
     return 0;
 }
diff --git a/distrib/utils/sysinst/arch/mac68k/md.h b/distrib/utils/sysinst/arch/mac68k/md.h
index bfabc135b39f..23304561973c 100644
--- a/distrib/utils/sysinst/arch/mac68k/md.h
+++ b/distrib/utils/sysinst/arch/mac68k/md.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: md.h,v 1.7 2000/12/22 10:12:15 mrg Exp $	*/
+/*	$NetBSD: md.h,v 1.8 2001/07/14 07:57:17 scottr Exp $	*/
 
 /*
  * Copyright 1997 Piermont Information Systems Inc.
@@ -179,16 +179,21 @@ EXTERN	char *disk_names[]
 
 /*
  * Machine-specific command to write a new label to a disk.
- * For example, i386  uses "/sbin/disklabel -w -r", just like i386
+ * For example, i386 uses "/sbin/disklabel -w -r", just like i386
  * miniroot scripts, though this may leave a bogus incore label.
- * Sun ports should probably use  DISKLABEL_CMD "/sbin/disklabel -w"
- * to get incore  to ondisk inode translation for the Sun proms.
- * If not defined, we assume the port does not support disklabels and  
+ * Sun ports should probably use DISKLABEL_CMD "/sbin/disklabel -w"
+ * to get incore to ondisk inode translation for the Sun proms.
+ * If not defined, we assume the port does not support disklabels and
  * hand-edited disklabel will NOT be written by MI code.
  *
  * The mac68k port doesn't support real disklabels so we don't define the
- * command string.  The Mac Disk Partition Map gets written in the
- * md_pre_disklabel() routine.
+ * command string. The Apple Disk Partition Map gets written in the
+ * md_pre_disklabel() routine, which also forces the incore copy to be
+ * updated. If native disklabels are supported or if disklabel() is
+ * fixed to work for writing labels, this command should be defined
+ * to a value that will force the writing of the label. In that case,
+ * the code in md_pre_disklabel() which forces the incore update can be
+ * removed, though its presence won't hurt.
  *
  * #define DISKLABEL_CMD
  */