diff --git a/sys/amd64/amd64/autoconf.c b/sys/amd64/amd64/autoconf.c
index afa38fd448da..8acbe10e2b1f 100644
--- a/sys/amd64/amd64/autoconf.c
+++ b/sys/amd64/amd64/autoconf.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)autoconf.c	7.1 (Berkeley) 5/9/91
- *	$Id: autoconf.c,v 1.41 1995/11/05 04:43:11 gibbs Exp $
+ *	$Id: autoconf.c,v 1.42 1995/11/20 12:09:54 phk Exp $
  */
 
 /*
@@ -75,6 +75,9 @@ static void setroot(void);
  */
 int	dkn;		/* number of iostat dk numbers assigned so far */
 
+#ifdef MFS_ROOT
+extern struct vfsops	mfs_vfsops;
+#endif
 #ifdef FFS
 extern struct vfsops	ufs_vfsops;
 #endif
@@ -90,11 +93,6 @@ int cd9660_mountroot __P((void *));
 #ifdef MSDOSFS
 int msdosfs_mountroot __P((void *));
 #endif
-#ifdef MFS_ROOT
-int mfs_initminiroot __P((u_char *));
-u_char mfs_root[MFS_ROOT*1024] = "MFS Filesystem goes here";
-u_char end_mfs_root[] = "MFS Filesystem had better STOP here";
-#endif
 
 #include "eisa.h"
 #include "isa.h"
@@ -199,10 +197,6 @@ configure(dummy)
 
 	cninit_finish();
 
-#ifdef MFS_ROOT
-	mfs_initminiroot(mfs_root);		/* XXX UGLY*/
-#endif /* MFS_ROOT */
-
 #ifdef CD9660
 	if ((boothowto & RB_CDROM) && !mountroot)
 		mountroot = find_cdrom_root;
@@ -213,6 +207,22 @@ configure(dummy)
 		mountroot = nfs_mountroot;
 #endif /* NFS */
 
+#ifdef MFS_ROOT
+	if (!mountroot) {
+		mountroot = vfs_mountroot;	/* XXX goes away*/
+		mountrootvfsops = &mfs_vfsops;
+		/*
+		 * Ignore the -a flag if this kernel isn't compiled
+		 * with a generic root/swap configuration: if we skip
+		 * setroot() and we aren't a generic kernel, chaos
+		 * will ensue because setconf() will be a no-op.
+		 * (rootdev is always initialized to NODEV in a
+		 * generic configuration, so we test for that.)
+		 */
+		if ((boothowto & RB_ASKNAME) == 0 || rootdev != NODEV)
+			setroot();
+	}
+#endif
 #ifdef FFS
 	if (!mountroot) {
 		mountroot = vfs_mountroot;	/* XXX goes away*/
diff --git a/sys/i386/i386/autoconf.c b/sys/i386/i386/autoconf.c
index afa38fd448da..8acbe10e2b1f 100644
--- a/sys/i386/i386/autoconf.c
+++ b/sys/i386/i386/autoconf.c
@@ -34,7 +34,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)autoconf.c	7.1 (Berkeley) 5/9/91
- *	$Id: autoconf.c,v 1.41 1995/11/05 04:43:11 gibbs Exp $
+ *	$Id: autoconf.c,v 1.42 1995/11/20 12:09:54 phk Exp $
  */
 
 /*
@@ -75,6 +75,9 @@ static void setroot(void);
  */
 int	dkn;		/* number of iostat dk numbers assigned so far */
 
+#ifdef MFS_ROOT
+extern struct vfsops	mfs_vfsops;
+#endif
 #ifdef FFS
 extern struct vfsops	ufs_vfsops;
 #endif
@@ -90,11 +93,6 @@ int cd9660_mountroot __P((void *));
 #ifdef MSDOSFS
 int msdosfs_mountroot __P((void *));
 #endif
-#ifdef MFS_ROOT
-int mfs_initminiroot __P((u_char *));
-u_char mfs_root[MFS_ROOT*1024] = "MFS Filesystem goes here";
-u_char end_mfs_root[] = "MFS Filesystem had better STOP here";
-#endif
 
 #include "eisa.h"
 #include "isa.h"
@@ -199,10 +197,6 @@ configure(dummy)
 
 	cninit_finish();
 
-#ifdef MFS_ROOT
-	mfs_initminiroot(mfs_root);		/* XXX UGLY*/
-#endif /* MFS_ROOT */
-
 #ifdef CD9660
 	if ((boothowto & RB_CDROM) && !mountroot)
 		mountroot = find_cdrom_root;
@@ -213,6 +207,22 @@ configure(dummy)
 		mountroot = nfs_mountroot;
 #endif /* NFS */
 
+#ifdef MFS_ROOT
+	if (!mountroot) {
+		mountroot = vfs_mountroot;	/* XXX goes away*/
+		mountrootvfsops = &mfs_vfsops;
+		/*
+		 * Ignore the -a flag if this kernel isn't compiled
+		 * with a generic root/swap configuration: if we skip
+		 * setroot() and we aren't a generic kernel, chaos
+		 * will ensue because setconf() will be a no-op.
+		 * (rootdev is always initialized to NODEV in a
+		 * generic configuration, so we test for that.)
+		 */
+		if ((boothowto & RB_ASKNAME) == 0 || rootdev != NODEV)
+			setroot();
+	}
+#endif
 #ifdef FFS
 	if (!mountroot) {
 		mountroot = vfs_mountroot;	/* XXX goes away*/
diff --git a/sys/ufs/mfs/mfs_vfsops.c b/sys/ufs/mfs/mfs_vfsops.c
index eafc84a22364..2b7ea253494e 100644
--- a/sys/ufs/mfs/mfs_vfsops.c
+++ b/sys/ufs/mfs/mfs_vfsops.c
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)mfs_vfsops.c	8.4 (Berkeley) 4/16/94
- * $Id: mfs_vfsops.c,v 1.14 1995/11/09 08:14:26 bde Exp $
+ * $Id: mfs_vfsops.c,v 1.15 1995/11/28 02:15:29 peter Exp $
  */
 
 #include <sys/param.h>
@@ -88,32 +88,12 @@ struct vfsops mfs_vfsops = {
 
 VFS_SET(mfs_vfsops, mfs, MOUNT_MFS, 0);
 
-/*
- * This is called early in boot to set the base address and size
- * of the mini-root.
- *
- * XXX THIS IS A DESIGN ERROR; THIS CODE SHOULD BE MOVED INTO
- * XXX THE ROOT MOUNT CODE IN "mfs_mount"!!!
- */
-int
-mfs_initminiroot(base)
-	caddr_t base;
-{
-	struct fs *fs = (struct fs *)(base + SBOFF);
+#ifdef MFS_ROOT
 
-	/* check for valid super block */
-	if (fs->fs_magic != FS_MAGIC || fs->fs_bsize > MAXBSIZE ||
-	    fs->fs_bsize < sizeof(struct fs))
-		return (0);
-	mountroot = vfs_mountroot;	/* XXX goes away*/
-	mountrootvfsops = &mfs_vfsops;
-	mfs_rootbase = base;
-	mfs_rootsize = fs->fs_fsize * fs->fs_size;
-	rootdev = makedev(255, mfs_minor++);
-	printf("rootfs is %ld Kbyte compiled in MFS\n",mfs_rootsize/1024);
-	return (mfs_rootsize);
-}
+u_char mfs_root[MFS_ROOT*1024] = "MFS Filesystem goes here";
+u_char end_mfs_root[] = "MFS Filesystem had better STOP here";
 
+#endif	/* MFS_ROOT */
 
 /*
  * mfs_mount
@@ -179,6 +159,23 @@ mfs_mount(mp, path, data, ndp, p)
 		 ***
 		 */
 
+#ifdef MFS_ROOT
+		/* Location of MFS/FFS superblock */
+		fs = (struct fs *)(mfs_root + SBOFF);
+
+		/* recheck for valid super block */
+		if (fs->fs_magic != FS_MAGIC || fs->fs_bsize > MAXBSIZE ||
+		    fs->fs_bsize < sizeof(struct fs)) {
+			panic("MFS image is invalid!!");
+		}
+
+		mfs_rootbase = mfs_root;
+		mfs_rootsize = fs->fs_fsize * fs->fs_size;
+		rootdev = makedev(255, mfs_minor++);
+		printf("rootfs is %ld Kbyte compiled in MFS\n",
+		       mfs_rootsize/1024);
+
+
 		/* Get vnode for root device*/
 		if( bdevvp( rootdev, &rootvp))
 			panic("mfs_mountroot: can't setup bdevvp for rootdev");
@@ -207,6 +204,10 @@ mfs_mount(mp, path, data, ndp, p)
 		}
 
 		goto dostatfs;		/* success*/
+#else
+		/* you loose */
+		panic("mfs_mount: mount MFS as root: not configured!");
+#endif /* MFS_ROOT */
 	}
 
 	/*