diff --git a/mkbootimg/Android.mk b/mkbootimg/Android.mk
index 2a97c26..0c9b0c6 100644
--- a/mkbootimg/Android.mk
+++ b/mkbootimg/Android.mk
@@ -4,6 +4,7 @@
 
 LOCAL_SRC_FILES := mkbootimg.c
 LOCAL_STATIC_LIBRARIES := libmincrypt
+LOCAL_CFLAGS := -Werror
 
 LOCAL_MODULE := mkbootimg
 
diff --git a/mkbootimg/mkbootimg.c b/mkbootimg/mkbootimg.c
index a7daccc..fc92b4d 100644
--- a/mkbootimg/mkbootimg.c
+++ b/mkbootimg/mkbootimg.c
@@ -77,7 +77,7 @@
 int write_padding(int fd, unsigned pagesize, unsigned itemsize)
 {
     unsigned pagemask = pagesize - 1;
-    unsigned count;
+    ssize_t count;
 
     if((itemsize & pagemask) == 0) {
         return 0;
@@ -108,7 +108,7 @@
     unsigned pagesize = 2048;
     int fd;
     SHA_CTX ctx;
-    uint8_t* sha;
+    const uint8_t* sha;
     unsigned base           = 0x10000000;
     unsigned kernel_offset  = 0x00008000;
     unsigned ramdisk_offset = 0x01000000;
@@ -189,7 +189,7 @@
         return usage();
     }
 
-    strcpy(hdr.name, board);
+    strcpy((char *) hdr.name, board);
 
     memcpy(hdr.magic, BOOT_MAGIC, BOOT_MAGIC_SIZE);
 
@@ -255,14 +255,14 @@
     if(write(fd, &hdr, sizeof(hdr)) != sizeof(hdr)) goto fail;
     if(write_padding(fd, pagesize, sizeof(hdr))) goto fail;
 
-    if(write(fd, kernel_data, hdr.kernel_size) != hdr.kernel_size) goto fail;
+    if(write(fd, kernel_data, hdr.kernel_size) != (ssize_t) hdr.kernel_size) goto fail;
     if(write_padding(fd, pagesize, hdr.kernel_size)) goto fail;
 
-    if(write(fd, ramdisk_data, hdr.ramdisk_size) != hdr.ramdisk_size) goto fail;
+    if(write(fd, ramdisk_data, hdr.ramdisk_size) != (ssize_t) hdr.ramdisk_size) goto fail;
     if(write_padding(fd, pagesize, hdr.ramdisk_size)) goto fail;
 
     if(second_data) {
-        if(write(fd, second_data, hdr.second_size) != hdr.second_size) goto fail;
+        if(write(fd, second_data, hdr.second_size) != (ssize_t) hdr.second_size) goto fail;
         if(write_padding(fd, pagesize, hdr.second_size)) goto fail;
     }