diff --git a/.travis.yml b/.travis.yml
index 543107f6ef..13e97b7299 100755
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,7 +21,7 @@ git:
 # that SDK is shortest and add it there.  In the case of major re-organizations,
 # just try to make the builds "about equal in run time"
 env:
-  - TRAVIS_TESTS="unix docs translations website" TRAVIS_BOARDS="feather_huzzah circuitplayground_express pca10056 pca10059 feather_nrf52832 feather_nrf52840_express makerdiary_nrf52840_mdk" TRAVIS_SDK=arm:nrf:esp8266
+  - TRAVIS_TESTS="unix docs translations website" TRAVIS_BOARDS="feather_huzzah circuitplayground_express grandcentral_m4_express pca10056 pca10059 feather_nrf52832 feather_nrf52840_express makerdiary_nrf52840_mdk" TRAVIS_SDK=arm:nrf:esp8266
   - TRAVIS_BOARDS="metro_m0_express metro_m4_express pirkey_m0 trellis_m4_express trinket_m0" TRAVIS_SDK=arm
   - TRAVIS_BOARDS="feather_radiofruit_zigbee gemma_m0 hallowing_m0_express itsybitsy_m0_express itsybitsy_m4_express meowmeow" TRAVIS_SDK=arm
   - TRAVIS_BOARDS="feather_m0_express_crickit feather_m0_rfm69 feather_m0_rfm9x feather_m4_express arduino_zero arduino_mkr1300" TRAVIS_SDK=arm
diff --git a/ports/atmel-samd/boards/grandcentral_m4_express/mpconfigboard.h b/ports/atmel-samd/boards/grandcentral_m4_express/mpconfigboard.h
index 0d2d65ba54..57078eaea9 100644
--- a/ports/atmel-samd/boards/grandcentral_m4_express/mpconfigboard.h
+++ b/ports/atmel-samd/boards/grandcentral_m4_express/mpconfigboard.h
@@ -3,7 +3,7 @@
 
 #define CIRCUITPY_MCU_FAMILY samd51
 
-// This is for Rev A which is green
+// This is for Rev B which is green and has the SD card slot at the edge of the board.
 
 #define MICROPY_HW_LED_TX   &(pin_PC30)
 #define MICROPY_HW_LED_RX   &(pin_PC31)
diff --git a/ports/atmel-samd/boards/grandcentral_m4_express/pins.c b/ports/atmel-samd/boards/grandcentral_m4_express/pins.c
index 9fbb901de9..081bb701e7 100644
--- a/ports/atmel-samd/boards/grandcentral_m4_express/pins.c
+++ b/ports/atmel-samd/boards/grandcentral_m4_express/pins.c
@@ -37,7 +37,7 @@ STATIC const mp_map_elem_t board_global_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_D6),  (mp_obj_t)&pin_PD20 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D7),  (mp_obj_t)&pin_PD21 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D8),  (mp_obj_t)&pin_PB18 },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_D9),  (mp_obj_t)&pin_PB19 },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_D9),  (mp_obj_t)&pin_PB02 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D10),  (mp_obj_t)&pin_PB22 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D11),  (mp_obj_t)&pin_PB23 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D12),  (mp_obj_t)&pin_PB00 },
@@ -56,13 +56,12 @@ STATIC const mp_map_elem_t board_global_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_RX1), (mp_obj_t)&pin_PB13 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D19), (mp_obj_t)&pin_PB13 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D20), (mp_obj_t)&pin_PB20 },
-    { MP_OBJ_NEW_QSTR(MP_QSTR_D21), (mp_obj_t)&pin_PB21 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_SDA), (mp_obj_t)&pin_PB20 },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_D21), (mp_obj_t)&pin_PB21 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_SCL), (mp_obj_t)&pin_PB21 },
 
-    // Not connected but probably should be.
-    //{ MP_OBJ_NEW_QSTR(MP_QSTR_D22), (mp_obj_t)&pin_PB01 },
-    //{ MP_OBJ_NEW_QSTR(MP_QSTR_D23), (mp_obj_t)&pin_PB01 },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_D22), (mp_obj_t)&pin_PD12 },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_D23), (mp_obj_t)&pin_PA15 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D24), (mp_obj_t)&pin_PC17 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_SCL1), (mp_obj_t)&pin_PC17 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D25), (mp_obj_t)&pin_PC16 },
@@ -73,7 +72,8 @@ STATIC const mp_map_elem_t board_global_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_PCC_DEN2), (mp_obj_t)&pin_PA13 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D28), (mp_obj_t)&pin_PA14 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_PCC_CLK), (mp_obj_t)&pin_PA14 },
-    // { MP_OBJ_NEW_QSTR(MP_QSTR_D29), (mp_obj_t)&pin_PB01 }, // TODO GCLK
+    { MP_OBJ_NEW_QSTR(MP_QSTR_D29), (mp_obj_t)&pin_PB19 },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_PCC_XCLK), (mp_obj_t)&pin_PB19 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D30), (mp_obj_t)&pin_PA23 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_PCC_D7), (mp_obj_t)&pin_PA23 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_D31), (mp_obj_t)&pin_PA22 },
@@ -122,6 +122,8 @@ STATIC const mp_map_elem_t board_global_dict_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_SD_CS), (mp_obj_t)&pin_PB28 },
     { MP_OBJ_NEW_QSTR(MP_QSTR_SD_MISO), (mp_obj_t)&pin_PB29 },
 
+    { MP_OBJ_NEW_QSTR(MP_QSTR_SD_CARD_DETECT), (mp_obj_t)&pin_PB31 },
+
     { MP_OBJ_NEW_QSTR(MP_QSTR_NEOPIXEL), (mp_obj_t)&pin_PC24 },
 
     { MP_OBJ_NEW_QSTR(MP_QSTR_LED_RX), (mp_obj_t)&pin_PC31 },