diff --git a/boot/bootutil/src/bootutil_priv.h b/boot/bootutil/src/bootutil_priv.h
index a5eb2df..0bdfb12 100644
--- a/boot/bootutil/src/bootutil_priv.h
+++ b/boot/bootutil/src/bootutil_priv.h
@@ -108,7 +108,7 @@
         struct image_header hdr;
         const struct flash_area *area;
         struct flash_area *sectors;
-        int num_sectors;
+        size_t num_sectors;
     } imgs[BOOT_NUM_SLOTS];
 
     const struct flash_area *scratch_area;
@@ -220,7 +220,7 @@
     if (rc != 0) {
         return rc;
     }
-    state->imgs[slot].num_sectors = num_sectors;
+    state->imgs[slot].num_sectors = (size_t)num_sectors;
     return 0;
 }
 
diff --git a/boot/bootutil/src/loader.c b/boot/bootutil/src/loader.c
index 5990b80..9af54fb 100644
--- a/boot/bootutil/src/loader.c
+++ b/boot/bootutil/src/loader.c
@@ -1196,7 +1196,7 @@
 boot_go(struct boot_rsp *rsp)
 {
     int swap_type;
-    int slot;
+    size_t slot;
     int rc;
     int fa_id;