diff --git a/boot/bootutil/src/cbor.c b/boot/bootutil/src/cbor.c
index c925ca0..6df028d 100644
--- a/boot/bootutil/src/cbor.c
+++ b/boot/bootutil/src/cbor.c
@@ -58,17 +58,12 @@
         data->base++;
         data->len--;
         return 0;
-    } else if (ext == 24) {
-        want = 1;
-    } else if (ext == 25) {
-        want = 2;
-    } else if (ext == 26) {
-        want = 4;
-    } else {
-        /* If we want uint64 support, add it above here. */
+    } else if (ext > 26) {
         return -1;
     }
 
+    want = 1 << (ext - 24);
+
     if (data->len + 1 < want) {
         return -1;
     }