diff --git a/inc/compat/MicroBitCompat.h b/inc/compat/MicroBitCompat.h
index 9052d867..6475f4df 100644
--- a/inc/compat/MicroBitCompat.h
+++ b/inc/compat/MicroBitCompat.h
@@ -348,11 +348,11 @@ const uint16_t MICROBIT_ID_MBED_TICKER       __attribute__ ((deprecated)) = 83;
 #define MICROBIT_ID_IO_P13                                      ID_PIN_P13
 #define MICROBIT_ID_IO_P14                                      ID_PIN_P14
 #define MICROBIT_ID_IO_P15                                      ID_PIN_P15
-#define MICROBIT_ID_IO_A1_RX                                    ID_PIN_P16 //#define MICROBIT_ID_IO_P16
-#define MICROBIT_ID_IO_A1_TX                                    ID_PIN_P17 //#define MICROBIT_ID_IO_P17
-#define MICROBIT_ID_IO_P18                                      ID_PIN_P18
-#define MICROBIT_ID_IO_A0_SCL                                   ID_PIN_P19
-#define MICROBIT_ID_IO_A0_SDA                                   ID_PIN_P20 //#define MICROBIT_ID_IO_P20 
+#define MICROBIT_ID_IO_P16                                      ID_PIN_P16
+#define MICROBIT_ID_IO_P17                                      ID_PIN_P17 //[Calliope] add
+#define MICROBIT_ID_IO_P18                                      ID_PIN_P18 //[Calliope] add
+#define MICROBIT_ID_IO_P19                                      ID_PIN_P19
+#define MICROBIT_ID_IO_P20                                      ID_PIN_P20
 #define MICROBIT_ID_LOGO                                        ID_PIN_LOGO
 
 // Calliope mini3
diff --git a/model/MicroBit.cpp b/model/MicroBit.cpp
index 79f63bb2..acba7789 100644
--- a/model/MicroBit.cpp
+++ b/model/MicroBit.cpp
@@ -71,7 +71,7 @@ MicroBit::MicroBit() :
     io(adc, touchSensor),
     serial(io.usbTx, io.usbRx, NRF_UARTE0),
     _i2c(io.sda, io.scl),
-    i2c(io.A0SDA, io.A0SCL),
+    i2c(io.P20, io.P20),
     power(_i2c, io, systemTimer),
     flash(_i2c, io, power),
     internalFlash(MICROBIT_STORAGE_PAGE, 1, MICROBIT_CODEPAGESIZE),