diff --git a/udev.h b/udev.h
index 00f1361016..e615b4c8bb 100644
--- a/udev.h
+++ b/udev.h
@@ -24,6 +24,7 @@
 #define UDEV_H
 
 #include "libsysfs/libsysfs.h"
+#include <stddef.h>
 #include <sys/param.h>
 
 #define COMMENT_CHARACTER		'#'
@@ -33,6 +34,9 @@
 #define GROUP_SIZE	30
 #define MODE_SIZE	8
 
+/* length of public data */
+#define UDEVICE_LEN (offsetof(struct udevice, bus_id))
+
 struct udevice {
 	char name[NAME_SIZE];
 	char owner[OWNER_SIZE];
@@ -43,11 +47,11 @@ struct udevice {
 	unsigned int mode;	/* not mode_t due to conflicting definitions in different libcs */
 	char symlink[NAME_SIZE];
 
-	/* fields that help us in building strings */
-	unsigned char bus_id[SYSFS_NAME_LEN];
-	unsigned char program_result[NAME_SIZE];
-	unsigned char kernel_number[NAME_SIZE];
-	unsigned char kernel_name[NAME_SIZE];
+	/* private data that help us in building strings */
+	char bus_id[SYSFS_NAME_LEN];
+	char program_result[NAME_SIZE];
+	char kernel_number[NAME_SIZE];
+	char kernel_name[NAME_SIZE];
 };
 
 #define strfieldcpy(to, from) \
diff --git a/udevdb.c b/udevdb.c
index c4e064fc11..e657fedcb2 100644
--- a/udevdb.c
+++ b/udevdb.c
@@ -58,8 +58,8 @@ int udevdb_add_dev(const char *path, const struct udevice *dev)
 	key.dsize = strlen(keystr) + 1;
 
 	data.dptr = (void *)dev;
-	data.dsize = sizeof(*dev);
-	
+	data.dsize = UDEVICE_LEN;
+
 	return tdb_store(udevdb, key, data, TDB_REPLACE); 
 }
 
@@ -77,7 +77,8 @@ int udevdb_get_dev(const char *path, struct udevice *dev)
 	if (data.dptr == NULL || data.dsize == 0)
 		return -ENODEV;
 
-	memcpy(dev, data.dptr, sizeof(*dev));
+	memset(dev, 0, sizeof(struct udevice));
+	memcpy(dev, data.dptr, UDEVICE_LEN);
 	return 0;
 }