diff --git a/mkbootimg/bootimg.h b/mkbootimg/bootimg.h
index 9171d85..5ab6195 100644
--- a/mkbootimg/bootimg.h
+++ b/mkbootimg/bootimg.h
@@ -15,6 +15,8 @@
 ** limitations under the License.
 */
 
+#include <stdint.h>
+
 #ifndef _BOOT_IMAGE_H_
 #define _BOOT_IMAGE_H_
 
@@ -28,31 +30,31 @@
 
 struct boot_img_hdr
 {
-    unsigned char magic[BOOT_MAGIC_SIZE];
+    uint8_t magic[BOOT_MAGIC_SIZE];
 
-    unsigned kernel_size;  /* size in bytes */
-    unsigned kernel_addr;  /* physical load addr */
+    uint32_t kernel_size;  /* size in bytes */
+    uint32_t kernel_addr;  /* physical load addr */
 
-    unsigned ramdisk_size; /* size in bytes */
-    unsigned ramdisk_addr; /* physical load addr */
+    uint32_t ramdisk_size; /* size in bytes */
+    uint32_t ramdisk_addr; /* physical load addr */
 
-    unsigned second_size;  /* size in bytes */
-    unsigned second_addr;  /* physical load addr */
+    uint32_t second_size;  /* size in bytes */
+    uint32_t second_addr;  /* physical load addr */
 
-    unsigned tags_addr;    /* physical addr for kernel tags */
-    unsigned page_size;    /* flash page size we assume */
-    unsigned unused[2];    /* future expansion: should be 0 */
+    uint32_t tags_addr;    /* physical addr for kernel tags */
+    uint32_t page_size;    /* flash page size we assume */
+    uint32_t unused[2];    /* future expansion: should be 0 */
 
-    unsigned char name[BOOT_NAME_SIZE]; /* asciiz product name */
+    uint8_t name[BOOT_NAME_SIZE]; /* asciiz product name */
 
-    unsigned char cmdline[BOOT_ARGS_SIZE];
+    uint8_t cmdline[BOOT_ARGS_SIZE];
 
-    unsigned id[8]; /* timestamp / checksum / sha1 / etc */
+    uint32_t id[8]; /* timestamp / checksum / sha1 / etc */
 
     /* Supplemental command line data; kept here to maintain
      * binary compatibility with older versions of mkbootimg */
-    unsigned char extra_cmdline[BOOT_EXTRA_ARGS_SIZE];
-};
+    uint8_t extra_cmdline[BOOT_EXTRA_ARGS_SIZE];
+} __attribute__((packed));
 
 /*
 ** +-----------------+ 
diff --git a/mkbootimg/mkbootimg.c b/mkbootimg/mkbootimg.c
index fc92b4d..31f76e4 100644
--- a/mkbootimg/mkbootimg.c
+++ b/mkbootimg/mkbootimg.c
@@ -96,24 +96,24 @@
 {
     boot_img_hdr hdr;
 
-    char *kernel_fn = 0;
-    void *kernel_data = 0;
-    char *ramdisk_fn = 0;
-    void *ramdisk_data = 0;
-    char *second_fn = 0;
-    void *second_data = 0;
+    char *kernel_fn = NULL;
+    void *kernel_data = NULL;
+    char *ramdisk_fn = NULL;
+    void *ramdisk_data = NULL;
+    char *second_fn = NULL;
+    void *second_data = NULL;
     char *cmdline = "";
-    char *bootimg = 0;
+    char *bootimg = NULL;
     char *board = "";
-    unsigned pagesize = 2048;
+    uint32_t pagesize = 2048;
     int fd;
     SHA_CTX ctx;
     const uint8_t* sha;
-    unsigned base           = 0x10000000;
-    unsigned kernel_offset  = 0x00008000;
-    unsigned ramdisk_offset = 0x01000000;
-    unsigned second_offset  = 0x00f00000;
-    unsigned tags_offset    = 0x00000100;
+    uint32_t base           = 0x10000000U;
+    uint32_t kernel_offset  = 0x00008000U;
+    uint32_t ramdisk_offset = 0x01000000U;
+    uint32_t second_offset  = 0x00f00000U;
+    uint32_t tags_offset    = 0x00000100U;
     size_t cmdlen;
 
     argc--;