diff --git a/ports/gprs_a9/mpconfigport.h b/ports/gprs_a9/mpconfigport.h
index 2a6f85033a89..d3d0cbb24b32 100644
--- a/ports/gprs_a9/mpconfigport.h
+++ b/ports/gprs_a9/mpconfigport.h
@@ -8,6 +8,8 @@
 #include <stdint.h>
 #include <unistd.h>
 
+#include "api_sys.h"
+
 // options to control how MicroPython is built
 
 
@@ -63,6 +65,8 @@
 #define MICROPY_ENABLE_SCHEDULER            (1)
 #define MICROPY_SCHEDULER_DEPTH             (8)
 #define MICROPY_COMP_CONST                  (1)
+#define MICROPY_BEGIN_ATOMIC_SECTION()      SYS_EnterCriticalSection()
+#define MICROPY_END_ATOMIC_SECTION(state)   SYS_ExitCriticalSection(state)
 
 // MCU definition
 #define MP_ENDIANNESS_LITTLE                (1)