diff --git a/boot/bootutil/src/bootutil_misc.c b/boot/bootutil/src/bootutil_misc.c
index ba8fa7f..a47fadf 100644
--- a/boot/bootutil/src/bootutil_misc.c
+++ b/boot/bootutil/src/bootutil_misc.c
@@ -467,7 +467,7 @@
         return BOOT_EBADVECT;
     }
 
-    if (state_slot0.image_ok != 0xff) {
+    if (state_slot0.image_ok != BOOT_IMAGE_UNSET) {
         /* Already confirmed. */
         return 0;
     }
diff --git a/boot/bootutil/src/bootutil_priv.h b/boot/bootutil/src/bootutil_priv.h
index 45ce625..925e7f3 100644
--- a/boot/bootutil/src/bootutil_priv.h
+++ b/boot/bootutil/src/bootutil_priv.h
@@ -90,6 +90,9 @@
 #define BOOT_FLAG_IMAGE_OK         0
 #define BOOT_FLAG_COPY_DONE        1
 
+#define BOOT_IMAGE_OK              0x01
+#define BOOT_IMAGE_UNSET           0xff
+
 extern const uint32_t BOOT_MAGIC_SZ;
 
 int bootutil_verify_sig(uint8_t *hash, uint32_t hlen, uint8_t *sig, int slen,
diff --git a/boot/bootutil/src/loader.c b/boot/bootutil/src/loader.c
index 782ab6c..886c099 100644
--- a/boot/bootutil/src/loader.c
+++ b/boot/bootutil/src/loader.c
@@ -798,7 +798,7 @@
     rc = boot_read_swap_state_by_id(FLASH_AREA_IMAGE_1, &swap_state);
     assert(rc == 0);
 
-    if (swap_state.image_ok == 0x01) {
+    if (swap_state.image_ok == BOOT_IMAGE_OK) {
         rc = boot_write_image_ok(fap);
         assert(rc == 0);
     }
@@ -957,7 +957,7 @@
                                             &swap_state);
             assert(rc == 0);
 
-            if (swap_state.image_ok == 0x01) {
+            if (swap_state.image_ok == BOOT_IMAGE_OK) {
                 rc = boot_write_image_ok(fap);
                 assert(rc == 0);
             }
@@ -1155,7 +1155,7 @@
         }
     }
 
-    if (state_slot0.image_ok == 0xff) {
+    if (state_slot0.image_ok == BOOT_IMAGE_UNSET) {
         rc = boot_write_image_ok(fap);
         if (rc != 0) {
             return rc;