diff --git a/targets/TARGET_NXP/mbed_rtx.h b/targets/TARGET_NXP/mbed_rtx.h
index f21e3f1ebc..6dda30ec3d 100644
--- a/targets/TARGET_NXP/mbed_rtx.h
+++ b/targets/TARGET_NXP/mbed_rtx.h
@@ -89,7 +89,7 @@
 #define INITIAL_SP              (0x20010000UL)
 #endif
 
-#elif defined(TARGET_LPC546XX)
+#elif defined(TARGET_MCU_LPC546XX)
 
 #ifndef INITIAL_SP
 #define INITIAL_SP              (0x20028000UL)