diff --git a/mtools-memset.patch b/mtools-memset.patch
new file mode 100644
index 0000000..c517653
--- /dev/null
+++ b/mtools-memset.patch
@@ -0,0 +1,13 @@
+--- mtools-3.9.9/fat.c.memset	2005-03-21 11:23:10.000000000 +0000
++++ mtools-3.9.9/fat.c	2005-03-21 11:23:36.000000000 +0000
+@@ -437,8 +437,8 @@
+ 		InfoSector_t *infoSector;
+ 		infoSector = (InfoSector_t *) safe_malloc(This->sector_size);
+ 		set_dword(infoSector->signature1, INFOSECT_SIGNATURE1);
+-		memset(infoSector->filler1, sizeof(infoSector->filler1),0);
+-		memset(infoSector->filler2, sizeof(infoSector->filler2),0);
++		memset(infoSector->filler1, 0, sizeof(infoSector->filler1));
++		memset(infoSector->filler2, 0, sizeof(infoSector->filler2));
+ 		set_dword(infoSector->signature2, INFOSECT_SIGNATURE2);
+ 		set_dword(infoSector->pos, This->last);
+ 		set_dword(infoSector->count, This->freeSpace);
diff --git a/mtools.spec b/mtools.spec
index 3a5df51..4d24df3 100644
--- a/mtools.spec
+++ b/mtools.spec
@@ -13,6 +13,7 @@ Patch2: mtools-gcc4.patch
 Patch3: mtools-3.9.7-bigdisk.patch
 Patch4: mtools-3.9.9-noargs.patch
 Patch5: mtools-3.9.9-badc.patch
+Patch6: mtools-memset.patch
 Prereq: /sbin/install-info
 
 BuildRequires: texinfo
@@ -33,6 +34,7 @@ Mtools should be installed if you need to use MS-DOS disks.
 %patch3 -p1 -b .big
 %patch4 -p1 -b .noargs
 %patch5 -p1 -b .badc
+%patch6 -p1 -b .memset
 
 %build
 %configure
@@ -68,6 +70,9 @@ fi
 %{_infodir}/*
 
 %changelog
+* Mon Mar 21 2005 Tim Waugh <twaugh@redhat.com>
+- Fixed memset() usage bug.
+
 * Tue Mar 15 2005 Tim Waugh <twaugh@redhat.com> 3.9.9-12
 - Fix build (bug #151135).