diff --git a/dosfstools-mdraid-partition.patch b/dosfstools-mdraid-partition.patch
index b2a4ec5..c3bbca5 100644
--- a/dosfstools-mdraid-partition.patch
+++ b/dosfstools-mdraid-partition.patch
@@ -11,10 +11,10 @@ Index: src/mkdosfs.c
 -	(statbuf.st_rdev & 0xff3f) == 0x0d00 || /* xd */
 -	(statbuf.st_rdev & 0xff3f) == 0x1600 )  /* hdc, hdd */
 +	(statbuf.st_rdev & 0xfff3f) == 0x00300 || 
-+        (major(statbuf.st_rdev) == 3  && (minor(statbuf.st_rdev) & 63) == 0) || /* hda, hdb */
-+	(major(statbuf.st_rdev) == 8  && (minor(statbuf.st_rdev) & 15) == 0) || /* sd */
-+	(major(statbuf.st_rdev) == 13 && (minor(statbuf.st_rdev) & 63) == 0) || /* xd */
-+	(major(statbuf.st_rdev) == 22 && (minor(statbuf.st_rdev) & 63) == 0))   /* hdc, hdd */
++        (major(statbuf.st_rdev) == 3  && (minor(statbuf.st_rdev) % 64) == 0) || /* hda, hdb */
++	(major(statbuf.st_rdev) == 8  && (minor(statbuf.st_rdev) % 16) == 0) || /* sd */
++	(major(statbuf.st_rdev) == 13 && (minor(statbuf.st_rdev) % 64) == 0) || /* xd */
++	(major(statbuf.st_rdev) == 22 && (minor(statbuf.st_rdev) % 64) == 0))   /* hdc, hdd */
  	)
        die ("Device partition expected, not making filesystem on entire device '%s' (use -I to override)");