diff --git a/sbin/fsck_msdos/boot.c b/sbin/fsck_msdos/boot.c
index 8632ce5d3dd0..9d3c19b2e081 100644
--- a/sbin/fsck_msdos/boot.c
+++ b/sbin/fsck_msdos/boot.c
@@ -27,7 +27,7 @@
 
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: boot.c,v 1.16 2014/07/07 19:04:37 christos Exp $");
+__RCSID("$NetBSD: boot.c,v 1.17 2014/11/03 18:55:04 jakllsch Exp $");
 #endif /* not lint */
 
 #include <stdlib.h>
@@ -184,7 +184,7 @@ readboot(int dosfs, struct bootblock *boot)
 		return FSFATAL;
 	}
 
-	boot->ClusterOffset = (boot->RootDirEnts * 32 + boot->BytesPerSec - 1)
+	boot->ClusterOffset = (int)(boot->RootDirEnts * 32 + boot->BytesPerSec - 1)
 	    / boot->BytesPerSec
 	    + boot->ResSectors
 	    + boot->FATs * boot->FATsecs
@@ -205,8 +205,8 @@ readboot(int dosfs, struct bootblock *boot)
 		boot->NumSectors = boot->HugeSectors;
 	boot->NumClusters = (boot->NumSectors - boot->ClusterOffset) / boot->SecPerClust;
 
-	if (boot->ClusterOffset > boot->NumSectors) {
-		pfatal("Cluster offset too large (%u clusters)\n",
+	if (boot->ClusterOffset > (intmax_t)boot->NumSectors) {
+		pfatal("Cluster offset too large (%d sectors)\n",
 		    boot->ClusterOffset);
 		return FSFATAL;
 	}
diff --git a/sbin/fsck_msdos/dosfs.h b/sbin/fsck_msdos/dosfs.h
index 0a3c963e9773..0afa96981bbf 100644
--- a/sbin/fsck_msdos/dosfs.h
+++ b/sbin/fsck_msdos/dosfs.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: dosfs.h,v 1.6 2008/06/13 20:46:09 martin Exp $	*/
+/*	$NetBSD: dosfs.h,v 1.7 2014/11/03 18:55:04 jakllsch Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996, 1997 Wolfgang Solfrank
@@ -70,7 +70,7 @@ struct bootblock {
 	u_int32_t NumSectors;		/* how many sectors are there */
 	u_int32_t FATsecs;		/* how many sectors are in FAT */
 	u_int32_t NumFatEntries;	/* how many entries really are there */
-	u_int	ClusterOffset;		/* at what sector would sector 0 start */
+	int	ClusterOffset;		/* at what sector would sector 0 start */
 	u_int	ClusterSize;		/* Cluster size in bytes */
 
 	/* Now some statistics: */