Index: head/usr.sbin/makefs/msdos.h
===================================================================
--- head/usr.sbin/makefs/msdos.h
+++ head/usr.sbin/makefs/msdos.h
@@ -51,6 +51,7 @@
 	size_t cn_namelen;
 };
 
+int msdosfs_fsiflush(struct msdosfsmount *);
 struct msdosfsmount *msdosfs_mount(struct vnode *);
 int msdosfs_root(struct msdosfsmount *, struct vnode *);
 
Index: head/usr.sbin/makefs/msdos.c
===================================================================
--- head/usr.sbin/makefs/msdos.c
+++ head/usr.sbin/makefs/msdos.c
@@ -203,6 +203,8 @@
 		errx(1, "Image file `%s' not created.", image);
 	TIMER_RESULTS(start, "msdos_populate_dir");
 
+	if (msdosfs_fsiflush(pmp) != 0)
+		errx(1, "Unable to update FSInfo block.");
 	if (debug & DEBUG_FS_MAKEFS)
 		putchar('\n');
 
Index: head/usr.sbin/makefs/msdos/msdosfs_vfsops.c
===================================================================
--- head/usr.sbin/makefs/msdos/msdosfs_vfsops.c
+++ head/usr.sbin/makefs/msdos/msdosfs_vfsops.c
@@ -359,3 +359,33 @@
 	vp->v_data = ndep;
 	return 0;
 }
+
+/*
+ * If we have an FSInfo block, update it.
+ */
+int
+msdosfs_fsiflush(struct msdosfsmount *pmp)
+{
+	struct fsinfo *fp;
+	struct buf *bp;
+	int error;
+
+	if (pmp->pm_fsinfo == 0 || (pmp->pm_flags & MSDOSFS_FSIMOD) == 0) {
+		error = 0;
+		goto out;
+	}
+	error = bread(pmp->pm_devvp, pmp->pm_fsinfo, pmp->pm_BytesPerSec,
+	    NOCRED, &bp);
+	if (error != 0) {
+		brelse(bp);
+		goto out;
+	}
+	fp = (struct fsinfo *)bp->b_data;
+	putulong(fp->fsinfree, pmp->pm_freeclustercount);
+	putulong(fp->fsinxtfree, pmp->pm_nxtfree);
+	pmp->pm_flags &= ~MSDOSFS_FSIMOD;
+	error = bwrite(bp);
+
+out:
+	return (error);
+}