diff --git a/boot/bootutil/include/bootutil/bootutil_public.h b/boot/bootutil/include/bootutil/bootutil_public.h
index 421d854b1..a0ee5872a 100644
--- a/boot/bootutil/include/bootutil/bootutil_public.h
+++ b/boot/bootutil/include/bootutil/bootutil_public.h
@@ -129,6 +129,14 @@ _Static_assert(MCUBOOT_BOOT_MAX_ALIGN >= 8 && MCUBOOT_BOOT_MAX_ALIGN <= 32,
                                                     (swap_info) = (image) << 4 \
                                                                 | (type);      \
                                                     }
+
+enum boot_slot {
+    BOOT_SLOT_PRIMARY = 0,      /* Primary slot */
+    BOOT_SLOT_SECONDARY = 1,    /* Secondary slot */
+    BOOT_SLOT_COUNT = 2,        /* Number of slots */
+    BOOT_SLOT_NONE = UINT32_MAX /* special value representing no active slot */
+};
+
 #ifdef MCUBOOT_HAVE_ASSERT_H
 #include "mcuboot_config/mcuboot_assert.h"
 #else
diff --git a/boot/bootutil/src/bootutil_priv.h b/boot/bootutil/src/bootutil_priv.h
index c0a285bbe..4e0260a50 100644
--- a/boot/bootutil/src/bootutil_priv.h
+++ b/boot/bootutil/src/bootutil_priv.h
@@ -51,7 +51,7 @@ struct flash_area;
 
 #define BOOT_TMPBUF_SZ  256
 
-#define NO_ACTIVE_SLOT UINT32_MAX
+#define NO_ACTIVE_SLOT BOOT_SLOT_NONE
 
 /** Number of image slots in flash; currently limited to two. */
 #if defined(MCUBOOT_SINGLE_APPLICATION_SLOT) || defined(MCUBOOT_SINGLE_APPLICATION_SLOT_RAM_LOAD)
@@ -222,8 +222,8 @@ _Static_assert(sizeof(boot_img_magic) == BOOT_MAGIC_SZ, "Invalid size for image
 /** Maximum number of image sectors supported by the bootloader. */
 #define BOOT_STATUS_MAX_ENTRIES         BOOT_MAX_IMG_SECTORS
 
-#define BOOT_PRIMARY_SLOT               0
-#define BOOT_SECONDARY_SLOT             1
+#define BOOT_PRIMARY_SLOT               BOOT_SLOT_PRIMARY
+#define BOOT_SECONDARY_SLOT             BOOT_SLOT_SECONDARY
 
 #define BOOT_STATUS_SOURCE_NONE         0
 #define BOOT_STATUS_SOURCE_SCRATCH      1