diff --git a/boot/bootutil/src/bootutil_misc.c b/boot/bootutil/src/bootutil_misc.c
index 8cab4c4..041f6a2 100644
--- a/boot/bootutil/src/bootutil_misc.c
+++ b/boot/bootutil/src/bootutil_misc.c
@@ -17,6 +17,10 @@
  * under the License.
  */
 
+/*
+ * Modifications are Copyright (c) 2019 Arm Limited.
+ */
+
 #include <assert.h>
 #include <string.h>
 #include <inttypes.h>
@@ -194,7 +198,7 @@
 }
 
 uint32_t
-boot_swap_type_off(const struct flash_area *fap)
+boot_swap_info_off(const struct flash_area *fap)
 {
     return fap->fa_size - BOOT_MAGIC_SZ - BOOT_MAX_ALIGN * 3;
 }
@@ -232,6 +236,7 @@
 {
     uint32_t magic[BOOT_MAGIC_ARR_SZ];
     uint32_t off;
+    uint8_t swap_info;
     int rc;
 
     off = boot_magic_off(fap);
@@ -245,14 +250,19 @@
         state->magic = boot_magic_decode(magic);
     }
 
-    off = boot_swap_type_off(fap);
-    rc = flash_area_read_is_empty(fap, off, &state->swap_type,
-            sizeof state->swap_type);
+    off = boot_swap_info_off(fap);
+    rc = flash_area_read_is_empty(fap, off, &swap_info, sizeof swap_info);
     if (rc < 0) {
         return BOOT_EFLASH;
     }
+
+    /* Extract the swap type and image number */
+    state->swap_type = BOOT_GET_SWAP_TYPE(swap_info);
+    state->image_num = BOOT_GET_IMAGE_NUM(swap_info);
+
     if (rc == 1 || state->swap_type > BOOT_SWAP_TYPE_REVERT) {
         state->swap_type = BOOT_SWAP_TYPE_NONE;
+        state->image_num = 0;
     }
 
     off = boot_copy_done_off(fap);
@@ -494,14 +504,18 @@
  * resume in case of an unexpected reset.
  */
 int
-boot_write_swap_type(const struct flash_area *fap, uint8_t swap_type)
+boot_write_swap_info(const struct flash_area *fap, uint8_t swap_type,
+                     uint8_t image_num)
 {
     uint32_t off;
+    uint8_t swap_info;
 
-    off = boot_swap_type_off(fap);
-    BOOT_LOG_DBG("writing swap_type; fa_id=%d off=0x%x (0x%x), swap_type=0x%x",
-                 fap->fa_id, off, fap->fa_off + off, swap_type);
-    return boot_write_trailer_byte(fap, off, swap_type);
+    BOOT_SET_SWAP_INFO(swap_info, image_num, swap_type);
+    off = boot_swap_info_off(fap);
+    BOOT_LOG_DBG("writing swap_info; fa_id=%d off=0x%x (0x%x), swap_type=0x%x"
+                 " image_num=0x%x",
+                 fap->fa_id, off, fap->fa_off + off, swap_type, image_num);
+    return boot_write_trailer_byte(fap, off, swap_info);
 }
 
 int
@@ -648,7 +662,7 @@
             } else {
                 swap_type = BOOT_SWAP_TYPE_TEST;
             }
-            rc = boot_write_swap_type(fap, swap_type);
+            rc = boot_write_swap_info(fap, swap_type, 0);
         }
 
         flash_area_close(fap);
diff --git a/boot/bootutil/src/bootutil_priv.h b/boot/bootutil/src/bootutil_priv.h
index d2871ee..bc35a72 100644
--- a/boot/bootutil/src/bootutil_priv.h
+++ b/boot/bootutil/src/bootutil_priv.h
@@ -17,6 +17,10 @@
  * under the License.
  */
 
+/*
+ * Modifications are Copyright (c) 2019 Arm Limited.
+ */
+
 #ifndef H_BOOTUTIL_PRIV_
 #define H_BOOTUTIL_PRIV_
 
@@ -106,7 +110,7 @@
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  *  |                      Swap size (4 octets)                     |
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
- *  |   Swap type   |           0xff padding (7 octets)             |
+ *  |   Swap info   |           0xff padding (7 octets)             |
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  *  |   Copy done   |           0xff padding (7 octets)             |
  *  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -127,11 +131,27 @@
     uint8_t swap_type;  /* One of the BOOT_SWAP_TYPE_[...] values. */
     uint8_t copy_done;  /* One of the BOOT_FLAG_[...] values. */
     uint8_t image_ok;   /* One of the BOOT_FLAG_[...] values. */
+    uint8_t image_num;  /* Boot status belongs to this image */
 };
 
 #define BOOT_MAX_IMG_SECTORS       MCUBOOT_MAX_IMG_SECTORS
 
 /*
+ * Extract the swap type and image number from image trailers's swap_info
+ * filed.
+ */
+#define BOOT_GET_SWAP_TYPE(swap_info)    ((swap_info) & 0x0F)
+#define BOOT_GET_IMAGE_NUM(swap_info)    ((swap_info) >> 4)
+
+/* Construct the swap_info field from swap type and image number */
+#define BOOT_SET_SWAP_INFO(swap_info, image, type)  {                          \
+                                                    assert((image) < 0xF);     \
+                                                    assert((type)  < 0xF);     \
+                                                    (swap_info) = (image) << 4 \
+                                                                | (type);      \
+                                                    }
+
+/*
  * The current flashmap API does not check the amount of space allocated when
  * loading sector data from the flash device, allowing for smaller counts here
  * would most surely incur in overruns.
@@ -194,7 +214,7 @@
 uint32_t boot_trailer_sz(uint8_t min_write_sz);
 int boot_status_entries(const struct flash_area *fap);
 uint32_t boot_status_off(const struct flash_area *fap);
-uint32_t boot_swap_type_off(const struct flash_area *fap);
+uint32_t boot_swap_info_off(const struct flash_area *fap);
 int boot_read_swap_state(const struct flash_area *fap,
                          struct boot_swap_state *state);
 int boot_read_swap_state_by_id(int flash_area_id,
@@ -204,7 +224,8 @@
 int boot_schedule_test_swap(void);
 int boot_write_copy_done(const struct flash_area *fap);
 int boot_write_image_ok(const struct flash_area *fap);
-int boot_write_swap_type(const struct flash_area *fap, uint8_t swap_type);
+int boot_write_swap_info(const struct flash_area *fap, uint8_t swap_type,
+                         uint8_t image_num);
 int boot_write_swap_size(const struct flash_area *fap, uint32_t swap_size);
 int boot_read_swap_size(uint32_t *swap_size);
 #ifdef MCUBOOT_ENC_IMAGES
diff --git a/boot/bootutil/src/loader.c b/boot/bootutil/src/loader.c
index c6ec34f..fcbf082 100644
--- a/boot/bootutil/src/loader.c
+++ b/boot/bootutil/src/loader.c
@@ -17,6 +17,10 @@
  * under the License.
  */
 
+/*
+ * Modifications are Copyright (c) 2019 Arm Limited.
+ */
+
 /**
  * This file provides an interface to the boot loader.  Functions defined in
  * this file should only be called while the boot loader is running.
@@ -522,6 +526,7 @@
 {
     const struct flash_area *fap;
     uint32_t off;
+    uint8_t swap_info;
     int status_loc;
     int area_id;
     int rc;
@@ -561,13 +566,15 @@
 
     rc = boot_read_status_bytes(fap, bs);
     if (rc == 0) {
-        off = boot_swap_type_off(fap);
-        rc = flash_area_read_is_empty(fap, off, &bs->swap_type,
-                                      sizeof bs->swap_type);
+        off = boot_swap_info_off(fap);
+        rc = flash_area_read_is_empty(fap, off, &swap_info, sizeof swap_info);
         if (rc == 1) {
-            bs->swap_type = BOOT_SWAP_TYPE_NONE;
+            BOOT_SET_SWAP_INFO(swap_info, 0, BOOT_SWAP_TYPE_NONE);
             rc = 0;
         }
+
+        /* Extract the swap type info */
+        bs->swap_type = BOOT_GET_SWAP_TYPE(swap_info);
     }
 
     flash_area_close(fap);
@@ -974,7 +981,9 @@
     assert(rc == 0);
 
     if (bs->swap_type != BOOT_SWAP_TYPE_NONE) {
-        rc = boot_write_swap_type(fap, bs->swap_type);
+        rc = boot_write_swap_info(fap,
+                                  bs->swap_type,
+                                  0);
         assert(rc == 0);
     }
 
@@ -1194,8 +1203,9 @@
             }
 
             if (swap_state.swap_type != BOOT_SWAP_TYPE_NONE) {
-                rc = boot_write_swap_type(fap_primary_slot,
-                                          swap_state.swap_type);
+                rc = boot_write_swap_info(fap_primary_slot,
+                                          swap_state.swap_type,
+                                          0);
                 assert(rc == 0);
             }