diff --git a/src/main/c/emulator/src/config.h b/src/main/c/emulator/src/config.h
index 191ae9f..6e251ad 100644
--- a/src/main/c/emulator/src/config.h
+++ b/src/main/c/emulator/src/config.h
@@ -3,7 +3,13 @@
 
 //#define QEMU
 #define SIM
+
+#ifndef OS_CALL
 #define OS_CALL 0xC0000000
+#endif
+
+#ifndef DTB
 #define DTB 0xC3000000
+#endif
 
 #endif