diff --git a/sim/mcuboot-sys/csupport/devicetree.h b/sim/mcuboot-sys/csupport/devicetree.h
index f268640..434e4ee 100644
--- a/sim/mcuboot-sys/csupport/devicetree.h
+++ b/sim/mcuboot-sys/csupport/devicetree.h
@@ -4,15 +4,17 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-/* This file mocks zephyr's autogenerated DT output header file */
+/* This file mocks zephyr's flash map / DT macro */
 
 #ifndef __DEVICETREE_H__
 #define __DEVICETREE_H__
 
-#define DT_FLASH_AREA_IMAGE_0_ID 1
-#define DT_FLASH_AREA_IMAGE_1_ID 2
-#define DT_FLASH_AREA_IMAGE_SCRATCH_ID 3
-#define DT_FLASH_AREA_IMAGE_2_ID 4
-#define DT_FLASH_AREA_IMAGE_3_ID 5
+#define FLASH_AREA_ID(x) FLASH_AREA_ID_##x
+
+#define FLASH_AREA_ID_image_0 1
+#define FLASH_AREA_ID_image_1 2
+#define FLASH_AREA_ID_image_scratch 3
+#define FLASH_AREA_ID_image_2 4
+#define FLASH_AREA_ID_image_3 5
 
 #endif /*__DEVICETREE_H__*/