diff --git a/sim/mcuboot-sys/build.rs b/sim/mcuboot-sys/build.rs
index df8c67e..620e84f 100644
--- a/sim/mcuboot-sys/build.rs
+++ b/sim/mcuboot-sys/build.rs
@@ -143,6 +143,9 @@
 
     if swap_move {
         conf.define("MCUBOOT_SWAP_USING_MOVE", None);
+    } else if !overwrite_only {
+        conf.define("CONFIG_BOOT_SWAP_USING_SCRATCH", None);
+        conf.define("MCUBOOT_SWAP_USING_SCRATCH", None);
     }
 
     if enc_rsa {