diff --git a/tools/firmware-utils/src/fw.h b/tools/firmware-utils/src/fw.h
index 53a92a573c..778143d2c4 100644
--- a/tools/firmware-utils/src/fw.h
+++ b/tools/firmware-utils/src/fw.h
@@ -19,6 +19,7 @@
 #ifndef FW_INCLUDED
 #define FW_INCLUDED
 
+#include <stdint.h>
 #include <sys/types.h>
 
 #define MAGIC_HEADER	"OPEN"
@@ -30,16 +31,16 @@
 #define PART_NAME_LENGTH 16
 
 typedef struct header {
-	char magic[MAGIC_LENGTH];
-	char version[256];
+	uint8_t magic[MAGIC_LENGTH];
+	uint8_t version[256];
 	u_int32_t crc;
 	u_int32_t pad;
 } __attribute__ ((packed)) header_t;
 
 typedef struct part {
-	char magic[MAGIC_LENGTH];
-	char name[PART_NAME_LENGTH];
-	char pad[12];
+	uint8_t magic[MAGIC_LENGTH];
+	uint8_t name[PART_NAME_LENGTH];
+	uint8_t pad[12];
 	u_int32_t memaddr;
 	u_int32_t index;
 	u_int32_t baseaddr;
@@ -54,13 +55,13 @@ typedef struct part_crc {
 } __attribute__ ((packed)) part_crc_t;
 
 typedef struct signature {
-	char magic[MAGIC_LENGTH];
+	uint8_t magic[MAGIC_LENGTH];
 	u_int32_t crc;
 	u_int32_t pad;
 } __attribute__ ((packed)) signature_t;
 
 typedef struct signature_rsa {
-	char magic[MAGIC_LENGTH];
+	uint8_t magic[MAGIC_LENGTH];
 //	u_int32_t crc;
 	unsigned char rsa_signature[256];
 	u_int32_t pad;
diff --git a/tools/firmware-utils/src/mkfwimage.c b/tools/firmware-utils/src/mkfwimage.c
index ff9011a0c4..591ce44a78 100644
--- a/tools/firmware-utils/src/mkfwimage.c
+++ b/tools/firmware-utils/src/mkfwimage.c
@@ -32,6 +32,7 @@
 #include <limits.h>
 #include <stdbool.h>
 #include "fw.h"
+#include "utils.h"
 
 typedef struct fw_layout_data {
 	u_int32_t	kern_start;
@@ -204,21 +205,20 @@ static void write_header(void* mem, const char *magic, const char* version)
 	header_t* header = mem;
 	memset(header, 0, sizeof(header_t));
 
-	memcpy(header->magic, magic, MAGIC_LENGTH);
-	strncpy(header->version, version, sizeof(header->version));
-	header->crc = htonl(crc32(0L, (unsigned char *)header,
-				sizeof(header_t) - 2 * sizeof(u_int32_t)));
+	FW_MEMCPY_STR(header->magic, magic);
+	FW_MEMCPY_STR(header->version, version);
+	header->crc = htonl(crc32(0L, (uint8_t*) header,
+			    sizeof(header_t) - 2 * sizeof(u_int32_t)));
 	header->pad = 0L;
 }
 
-
 static void write_signature(void* mem, u_int32_t sig_offset)
 {
 	/* write signature */
 	signature_t* sign = (signature_t*)(mem + sig_offset);
 	memset(sign, 0, sizeof(signature_t));
 
-	memcpy(sign->magic, MAGIC_END, MAGIC_LENGTH);
+	FW_MEMCPY_STR(sign->magic, MAGIC_END);
 	sign->crc = htonl(crc32(0L,(unsigned char *)mem, sig_offset));
 	sign->pad = 0L;
 }
@@ -229,7 +229,7 @@ static void write_signature_rsa(void* mem, u_int32_t sig_offset)
 	signature_rsa_t* sign = (signature_rsa_t*)(mem + sig_offset);
 	memset(sign, 0, sizeof(signature_rsa_t));
 
-	memcpy(sign->magic, MAGIC_ENDS, MAGIC_LENGTH);
+	FW_MEMCPY_STR(sign->magic, MAGIC_ENDS);
 //	sign->crc = htonl(crc32(0L,(unsigned char *)mem, sig_offset));
 	sign->pad = 0L;
 }
@@ -259,8 +259,8 @@ static int write_part(void* mem, part_data_t* d)
 	munmap(addr, d->stats.st_size);
 
 	memset(p->name, 0, PART_NAME_LENGTH);
-	memcpy(p->magic, MAGIC_PART, MAGIC_LENGTH);
-	memcpy(p->name, d->partition_name, PART_NAME_LENGTH);
+	FW_MEMCPY_STR(p->magic, MAGIC_PART);
+	FW_MEMCPY_STR(p->name, d->partition_name);
 
 	p->index = htonl(d->partition_index);
 	p->data_size = htonl(d->stats.st_size);
diff --git a/tools/firmware-utils/src/utils.h b/tools/firmware-utils/src/utils.h
new file mode 100644
index 0000000000..11ec740069
--- /dev/null
+++ b/tools/firmware-utils/src/utils.h
@@ -0,0 +1,11 @@
+#include <stdint.h>
+#include <string.h>
+
+#pragma once
+
+#define FW_MEMCPY_STR(dst, src)					\
+       do {							\
+               size_t slen = strlen(src);			\
+               size_t dlen = sizeof(dst);			\
+               memcpy(dst, src, slen > dlen ? dlen : slen);	\
+       } while (0);