diff --git a/include/crc32.h b/include/crc32.h
index 0d34da0d249..c78d291b016 100644
--- a/include/crc32.h
+++ b/include/crc32.h
@@ -10,7 +10,8 @@
 
 extern uint32_t ul_crc32(uint32_t seed, const unsigned char *buf, size_t len);
 extern uint32_t ul_crc32_exclude_offset(uint32_t seed, const unsigned char *buf, size_t len,
-		                              size_t exclude_off, size_t exclude_len);
+		                              size_t exclude_off, size_t exclude_len,
+					      uint8_t exclude_fill);
 
 #endif
 
diff --git a/lib/crc32.c b/lib/crc32.c
index 824693d017a..b62b9f63807 100644
--- a/lib/crc32.c
+++ b/lib/crc32.c
@@ -122,7 +122,7 @@ uint32_t ul_crc32(uint32_t seed, const unsigned char *buf, size_t len)
 }
 
 uint32_t ul_crc32_exclude_offset(uint32_t seed, const unsigned char *buf, size_t len,
-			      size_t exclude_off, size_t exclude_len)
+			      size_t exclude_off, size_t exclude_len, uint8_t exclude_fill)
 {
 	uint32_t crc = seed;
 	const unsigned char *p = buf;
@@ -132,7 +132,7 @@ uint32_t ul_crc32_exclude_offset(uint32_t seed, const unsigned char *buf, size_t
 		unsigned char x = *p++;
 
 		if (i >= exclude_off && i < exclude_off + exclude_len)
-			x = 0;
+			x = exclude_fill;
 
 		crc = crc32_add_char(crc, x);
 	}
diff --git a/libblkid/src/partitions/gpt.c b/libblkid/src/partitions/gpt.c
index a8846be21f2..dc5bcf3aa44 100644
--- a/libblkid/src/partitions/gpt.c
+++ b/libblkid/src/partitions/gpt.c
@@ -106,7 +106,7 @@ struct gpt_entry {
 static inline uint32_t count_crc32(const unsigned char *buf, size_t len,
 				   size_t exclude_off, size_t exclude_len)
 {
-	return (ul_crc32_exclude_offset(~0L, buf, len, exclude_off, exclude_len) ^ ~0L);
+	return (ul_crc32_exclude_offset(~0L, buf, len, exclude_off, exclude_len, 0) ^ ~0L);
 }
 
 static inline const unsigned char *get_lba_buffer(blkid_probe pr,
diff --git a/libblkid/src/superblocks/cramfs.c b/libblkid/src/superblocks/cramfs.c
index 6a8731f7bf7..d9f3ed19d8a 100644
--- a/libblkid/src/superblocks/cramfs.c
+++ b/libblkid/src/superblocks/cramfs.c
@@ -64,7 +64,7 @@ static int cramfs_verify_csum(blkid_probe pr, const struct blkid_idmag *mag,
 
 	crc = ~ul_crc32_exclude_offset(~0LL, csummed, csummed_size,
 			offsetof(struct cramfs_super, info.crc),
-			sizeof_member(struct cramfs_super, info.crc));
+			sizeof_member(struct cramfs_super, info.crc), 0);
 
 	return blkid_probe_verify_csum(pr, crc, expected);
 }
diff --git a/libblkid/src/superblocks/ddf_raid.c b/libblkid/src/superblocks/ddf_raid.c
index a7cf32cf409..bf346330f9c 100644
--- a/libblkid/src/superblocks/ddf_raid.c
+++ b/libblkid/src/superblocks/ddf_raid.c
@@ -13,6 +13,7 @@
 #include <string.h>
 #include <stdint.h>
 
+#include "crc32.h"
 #include "superblocks.h"
 
 /* http://www.snia.org/standards/home */
@@ -71,25 +72,39 @@ struct ddf_header {
 	uint8_t		pad4[256];	/* 0xff */
 } __attribute__((packed));
 
+static int ddf_verify_csum(blkid_probe pr, const struct ddf_header *ddf)
+{
+	uint32_t expected, crc;
+
+	expected = be32_to_cpu(ddf->crc);
+
+	crc = ul_crc32_exclude_offset(0,
+				      (const unsigned char *)ddf, sizeof(*ddf),
+				      offsetof(__typeof__(*ddf), crc),
+				      sizeof_member(__typeof__(*ddf), crc),
+				      0xff);
+
+	return blkid_probe_verify_csum(pr, crc, expected);
+}
+
 static int probe_ddf(blkid_probe pr,
 		const struct blkid_idmag *mag __attribute__((__unused__)))
 {
 	int hdrs[] = { 1, 257 };
 	size_t i;
-	struct ddf_header *ddf = NULL;
+	const struct ddf_header *ddf = NULL;
 	char version[DDF_REV_LENGTH + 1];
 	uint64_t off = 0, lba;
 
 	for (i = 0; i < ARRAY_SIZE(hdrs); i++) {
 		off = ((pr->size / 0x200) - hdrs[i]) * 0x200;
 
-		ddf = (struct ddf_header *) blkid_probe_get_buffer(pr,
+		ddf = (const struct ddf_header *) blkid_probe_get_buffer(pr,
 					off,
 					sizeof(struct ddf_header));
 		if (!ddf)
 			return errno ? -errno : 1;
-		if (ddf->signature == cpu_to_be32(DDF_MAGIC) ||
-		    ddf->signature == cpu_to_le32(DDF_MAGIC))
+		if (ddf->signature == cpu_to_be32(DDF_MAGIC) && ddf_verify_csum(pr, ddf))
 			break;
 		ddf = NULL;
 	}
@@ -97,9 +112,7 @@ static int probe_ddf(blkid_probe pr,
 	if (!ddf)
 		return 1;
 
-	lba = ddf->signature == cpu_to_be32(DDF_MAGIC) ?
-			be64_to_cpu(ddf->primary_lba) :
-			le64_to_cpu(ddf->primary_lba);
+	lba = be64_to_cpu(ddf->primary_lba);
 
 	if (lba > 0) {
 		/* check primary header */
@@ -123,7 +136,7 @@ static int probe_ddf(blkid_probe pr,
 		return 1;
 	if (blkid_probe_set_magic(pr, off,
 			sizeof(ddf->signature),
-			(unsigned char *) &ddf->signature))
+			(const unsigned char *) &ddf->signature))
 		return 1;
 	return 0;
 }
diff --git a/libblkid/src/superblocks/zonefs.c b/libblkid/src/superblocks/zonefs.c
index e8fcab34fe3..8534e2ffe40 100644
--- a/libblkid/src/superblocks/zonefs.c
+++ b/libblkid/src/superblocks/zonefs.c
@@ -54,7 +54,7 @@ static int zonefs_verify_csum(blkid_probe pr, const struct zonefs_super *sb)
 	uint32_t expected = le32_to_cpu(sb->s_crc);
 	uint32_t crc = ul_crc32_exclude_offset(
 			~0LL, (unsigned char *) sb, sizeof(*sb),
-		       offsetof(__typeof__(*sb), s_crc), sizeof(sb->s_crc));
+		       offsetof(__typeof__(*sb), s_crc), sizeof(sb->s_crc), 0);
 	return blkid_probe_verify_csum(pr, crc, expected);
 }
 
diff --git a/libfdisk/src/gpt.c b/libfdisk/src/gpt.c
index 374246ce6be..2f850fa8a12 100644
--- a/libfdisk/src/gpt.c
+++ b/libfdisk/src/gpt.c
@@ -1043,7 +1043,7 @@ static unsigned char *gpt_read_entries(struct fdisk_context *cxt,
 static inline uint32_t count_crc32(const unsigned char *buf, size_t len,
 				   size_t ex_off, size_t ex_len)
 {
-	return (ul_crc32_exclude_offset(~0L, buf, len, ex_off, ex_len) ^ ~0L);
+	return (ul_crc32_exclude_offset(~0L, buf, len, ex_off, ex_len, 0) ^ ~0L);
 }
 
 static inline uint32_t gpt_header_count_crc32(struct gpt_header *header)