diff --git a/.github/workflows/test-builds.yml b/.github/workflows/test-builds.yml
index 301165fcd..59722e3ca 100644
--- a/.github/workflows/test-builds.yml
+++ b/.github/workflows/test-builds.yml
@@ -32,6 +32,7 @@ jobs:
         - megaatmega2560
         - teensy31
         - teensy35
+        - SAMD51_grandcentral_m4
 
         # Extended AVR Environments
 
@@ -75,7 +76,6 @@ jobs:
         #- mks_robin_lite
         #- mks_robin_mini
         #- mks_robin_nano
-        #- SAMD51_grandcentral_m4
 
     steps:
 
diff --git a/Marlin/src/HAL/HAL_SAMD51/timers.h b/Marlin/src/HAL/HAL_SAMD51/timers.h
index 9bd2e03d6..7ebd1b140 100644
--- a/Marlin/src/HAL/HAL_SAMD51/timers.h
+++ b/Marlin/src/HAL/HAL_SAMD51/timers.h
@@ -29,7 +29,7 @@
 typedef uint32_t hal_timer_t;
 #define HAL_TIMER_TYPE_MAX 0xFFFFFFFF
 
-#define HAL_TIMER_RATE      SystemCoreClock  // frequency of timers peripherals
+#define HAL_TIMER_RATE      F_CPU   // frequency of timers peripherals
 
 #define STEP_TIMER_NUM      0  // index of timer to use for stepper (also +1 for 32bits counter)
 #define PULSE_TIMER_NUM     STEP_TIMER_NUM
diff --git a/Marlin/src/core/boards.h b/Marlin/src/core/boards.h
index 904c25d86..4ba9840d8 100644
--- a/Marlin/src/core/boards.h
+++ b/Marlin/src/core/boards.h
@@ -295,7 +295,6 @@
 #define BOARD_GTM32_MINI_A30          4022  // STM32F103VET6 controller
 #define BOARD_GTM32_REV_B             4023  // STM32F103VET6 controller
 
-
 //
 // ARM Cortex-M4F
 //
@@ -340,6 +339,11 @@
 #define BOARD_MRR_ESPE                6002
 #define BOARD_E4D_BOX                 6003  // E4d@BOX
 
+//
+// SAMD51 ARM Cortex M4
+//
+#define BOARD_AGCM4_RAMPS_144         6100  // RAMPS 1.4.4
+
 //
 // Simulations
 //
diff --git a/Marlin/src/pins/pins.h b/Marlin/src/pins/pins.h
index 941b21bbb..3ba15c132 100644
--- a/Marlin/src/pins/pins.h
+++ b/Marlin/src/pins/pins.h
@@ -578,6 +578,13 @@
 #elif MB(E4D_BOX)
   #include "esp32/pins_E4D.h"                   // ESP32                                  env:esp32
 
+//
+// Adafruit Grand Central M4 (SAMD51 ARM Cortex-M4)
+//
+
+#elif MB(AGCM4_RAMPS_144)
+  #include "samd/pins_RAMPS_144.h"              // SAMD51                                 env:SAMD51_grandcentral_m4
+
 //
 // Linux Native Debug board
 //
diff --git a/Marlin/src/pins/samd/pins_RAMPS_144.h b/Marlin/src/pins/samd/pins_RAMPS_144.h
new file mode 100644
index 000000000..107ef9f57
--- /dev/null
+++ b/Marlin/src/pins/samd/pins_RAMPS_144.h
@@ -0,0 +1,611 @@
+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+/**
+ * AGCM4 with RAMPS v1.4.4 pin assignments
+ */
+
+#ifndef ARDUINO_GRAND_CENTRAL_M4
+  #error "Oops! Select 'Adafruit Grand Central M4' in 'Tools > Board.'"
+#endif
+
+#ifndef BOARD_INFO_NAME
+  #define BOARD_INFO_NAME "AGCM4 RAMPS 1.4.4"
+#endif
+
+//
+// Servos
+//
+#define SERVO0_PIN         11
+#define SERVO1_PIN          6
+#define SERVO2_PIN          5
+#define SERVO3_PIN          4
+
+//
+// EEPROM
+//
+#define E2END 0x7FFF  // 32Kb (24lc256)
+#define I2C_EEPROM    // EEPROM on I2C-0
+
+//
+// Limit Switches
+//
+#define X_MIN_PIN           3
+#define X_MAX_PIN           2
+#define Y_MIN_PIN          14
+#define Y_MAX_PIN          15
+#define Z_MIN_PIN          18
+#define Z_MAX_PIN          19
+
+//
+// Z Probe (when not Z_MIN_PIN)
+//
+#ifndef Z_MIN_PROBE_PIN
+  #define Z_MIN_PROBE_PIN  18
+#endif
+
+//
+// Steppers
+//
+#define X_STEP_PIN         67     // Mega/Due:54 - AGCM4:67
+#define X_DIR_PIN          68     // Mega/Due:55 - AGCM4:68
+#define X_ENABLE_PIN       38
+#ifndef X_CS_PIN
+  #define X_CS_PIN         47
+#endif
+
+#define Y_STEP_PIN         73     // Mega/Due:60 - AGCM4:73
+#define Y_DIR_PIN          74     // Mega/Due:61 - AGCM4:74
+#define Y_ENABLE_PIN       69     // Mega/Due:56 - AGCM4:69
+#ifndef Y_CS_PIN
+  #define Y_CS_PIN         45
+#endif
+
+#define Z_STEP_PIN         46
+#define Z_DIR_PIN          48
+#define Z_ENABLE_PIN       54     // Mega/Due:62 - AGCM4:54
+#ifndef Z_CS_PIN
+  #define Z_CS_PIN         32
+#endif
+
+#define Z2_STEP_PIN        36
+#define Z2_DIR_PIN         34
+#define Z2_ENABLE_PIN      30
+#ifndef Z2_CS_PIN
+  #define Z2_CS_PIN        22
+#endif
+
+#define E0_STEP_PIN        26
+#define E0_DIR_PIN         28
+#define E0_ENABLE_PIN      24
+#ifndef E0_CS_PIN
+  #define E0_CS_PIN        43
+#endif
+
+//
+// Temperature Sensors
+//
+#define TEMP_0_PIN         13
+#define TEMP_BED_PIN       14
+#define TEMP_CHAMBER_PIN   15
+
+//
+// Heaters / Fans
+//
+#define HEATER_0_PIN       10
+#define HEATER_BED_PIN      8
+#define FAN_PIN             9
+#define FAN1_PIN            7
+#define FAN2_PIN           12
+
+//
+// Misc. Functions
+//
+#define SDSS               53
+#define LED_PIN            13
+
+#ifndef FILWIDTH_PIN
+  #define FILWIDTH_PIN      5   // Analog Input on AUX2
+#endif
+
+// RAMPS 1.4 DIO 4 on the servos connector
+#ifndef FIL_RUNOUT_PIN
+  #define FIL_RUNOUT_PIN    4
+#endif
+
+#ifndef PS_ON_PIN
+  #define PS_ON_PIN        39
+#endif
+
+#if ENABLED(CASE_LIGHT_ENABLE) && !defined(CASE_LIGHT_PIN) && !defined(SPINDLE_LASER_ENA_PIN)
+  #if NUM_SERVOS <= 1 // Prefer the servo connector
+    #define CASE_LIGHT_PIN  6   // Hardware PWM
+  #endif
+#endif
+
+//
+// M3/M4/M5 - Spindle/Laser Control
+//
+#if HAS_CUTTER && !defined(SPINDLE_LASER_ENA_PIN)
+  #if !NUM_SERVOS                      // Use servo connector if possible
+    #define SPINDLE_LASER_ENA_PIN  4   // Pullup or pulldown!
+    #define SPINDLE_LASER_PWM_PIN  6   // Hardware PWM
+    #define SPINDLE_DIR_PIN        5
+  #else
+    #error "No auto-assignable Spindle/Laser pins available."
+  #endif
+#endif
+
+//
+// TMC software SPI
+//
+#if ENABLED(TMC_USE_SW_SPI)
+  #ifndef TMC_SW_MOSI
+    #define TMC_SW_MOSI    58     // Mega/Due:66 - AGCM4:58
+  #endif
+  #ifndef TMC_SW_MISO
+    #define TMC_SW_MISO    44
+  #endif
+  #ifndef TMC_SW_SCK
+    #define TMC_SW_SCK     56     // Mega/Due:64 - AGCM4:56
+  #endif
+#endif
+
+#if HAS_TMC220x
+  /**
+   * TMC2208/TMC2209 stepper drivers
+   *
+   * Hardware serial communication ports.
+   * If undefined software serial is used according to the pins below
+   */
+  //#define X_HARDWARE_SERIAL  Serial1
+  //#define X2_HARDWARE_SERIAL Serial1
+  //#define Y_HARDWARE_SERIAL  Serial1
+  //#define Y2_HARDWARE_SERIAL Serial1
+  //#define Z_HARDWARE_SERIAL  Serial1
+  //#define Z2_HARDWARE_SERIAL Serial1
+  //#define E0_HARDWARE_SERIAL Serial1
+  //#define E1_HARDWARE_SERIAL Serial1
+  //#define E2_HARDWARE_SERIAL Serial1
+  //#define E3_HARDWARE_SERIAL Serial1
+  //#define E4_HARDWARE_SERIAL Serial1
+
+  //
+  // Software serial
+  //
+
+  #ifndef X_SERIAL_TX_PIN
+    #define X_SERIAL_TX_PIN  47
+  #endif
+  #ifndef X_SERIAL_RX_PIN
+    #define X_SERIAL_RX_PIN  47
+  #endif
+  #ifndef X2_SERIAL_TX_PIN
+    #define X2_SERIAL_TX_PIN -1
+  #endif
+  #ifndef X2_SERIAL_RX_PIN
+    #define X2_SERIAL_RX_PIN -1
+  #endif
+
+  #ifndef Y_SERIAL_TX_PIN
+    #define Y_SERIAL_TX_PIN  45
+  #endif
+  #ifndef Y_SERIAL_RX_PIN
+    #define Y_SERIAL_RX_PIN  45
+  #endif
+  #ifndef Y2_SERIAL_TX_PIN
+    #define Y2_SERIAL_TX_PIN -1
+  #endif
+  #ifndef Y2_SERIAL_RX_PIN
+    #define Y2_SERIAL_RX_PIN -1
+  #endif
+
+  #ifndef Z_SERIAL_TX_PIN
+    #define Z_SERIAL_TX_PIN  32
+  #endif
+  #ifndef Z_SERIAL_RX_PIN
+    #define Z_SERIAL_RX_PIN  32
+  #endif
+  #ifndef Z2_SERIAL_TX_PIN
+    #define Z2_SERIAL_TX_PIN 22
+  #endif
+  #ifndef Z2_SERIAL_RX_PIN
+    #define Z2_SERIAL_RX_PIN 22
+  #endif
+
+  #ifndef E0_SERIAL_TX_PIN
+    #define E0_SERIAL_TX_PIN 43
+  #endif
+  #ifndef E0_SERIAL_RX_PIN
+    #define E0_SERIAL_RX_PIN 43
+  #endif
+  #ifndef E1_SERIAL_TX_PIN
+    #define E1_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E1_SERIAL_RX_PIN
+    #define E1_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E2_SERIAL_TX_PIN
+    #define E2_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E2_SERIAL_RX_PIN
+    #define E2_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E3_SERIAL_TX_PIN
+    #define E3_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E3_SERIAL_RX_PIN
+    #define E3_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E4_SERIAL_TX_PIN
+    #define E4_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E4_SERIAL_RX_PIN
+    #define E4_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E5_SERIAL_TX_PIN
+    #define E5_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E5_SERIAL_RX_PIN
+    #define E5_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E6_SERIAL_TX_PIN
+    #define E6_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E6_SERIAL_RX_PIN
+    #define E6_SERIAL_RX_PIN -1
+  #endif
+  #ifndef E7_SERIAL_TX_PIN
+    #define E7_SERIAL_TX_PIN -1
+  #endif
+  #ifndef E7_SERIAL_RX_PIN
+    #define E7_SERIAL_RX_PIN -1
+  #endif
+#endif
+
+//////////////////////////
+// LCDs and Controllers //
+//////////////////////////
+
+#if HAS_SPI_LCD
+
+  //
+  // LCD Display output pins
+  //
+  #if ENABLED(REPRAPWORLD_GRAPHICAL_LCD)
+
+    // TO TEST
+    // #define LCD_PINS_RS         49   // CS chip select /SS chip slave select
+    // #define LCD_PINS_ENABLE     51   // SID (MOSI)
+    // #define LCD_PINS_D4         52   // SCK (CLK) clock
+
+  #elif BOTH(NEWPANEL, PANEL_ONE)
+
+    // TO TEST
+    // #define LCD_PINS_RS         40
+    // #define LCD_PINS_ENABLE     42
+    // #define LCD_PINS_D4         57     // Mega/Due:65 - AGCM4:57
+    // #define LCD_PINS_D5         58     // Mega/Due:66 - AGCM4:58
+    // #define LCD_PINS_D6         44
+    // #define LCD_PINS_D7         56     // Mega/Due:64 - AGCM4:56
+
+  #else
+
+    #if ENABLED(CR10_STOCKDISPLAY)
+
+      // TO TEST
+      // #define LCD_PINS_RS       27
+      // #define LCD_PINS_ENABLE   29
+      // #define LCD_PINS_D4       25
+
+      #if DISABLED(NEWPANEL)
+        // TO TEST
+        // #define BEEPER_PIN      37
+      #endif
+
+    #elif ENABLED(ZONESTAR_LCD)
+
+      // TO TEST
+      // #define LCD_PINS_RS       56     // Mega/Due:64 - AGCM4:56
+      // #define LCD_PINS_ENABLE   44
+      // #define LCD_PINS_D4       55     // Mega/Due:63 - AGCM4:55
+      // #define LCD_PINS_D5       40
+      // #define LCD_PINS_D6       42
+      // #define LCD_PINS_D7       57     // Mega/Due:65 - AGCM4:57
+
+    #else
+
+      #if EITHER(MKS_12864OLED, MKS_12864OLED_SSD1306)
+        // TO TEST
+        // #define LCD_PINS_DC     25   // Set as output on init
+        // #define LCD_PINS_RS     27   // Pull low for 1s to init
+        // DOGM SPI LCD Support
+        // #define DOGLCD_CS       16
+        // #define DOGLCD_MOSI     17
+        // #define DOGLCD_SCK      23
+        // #define DOGLCD_A0       LCD_PINS_DC
+      #else
+        #define LCD_PINS_RS        16
+        #define LCD_PINS_ENABLE    17
+        #define LCD_PINS_D4        23
+        #define LCD_PINS_D5        25
+        #define LCD_PINS_D6        27
+      #endif
+
+      #define LCD_PINS_D7          29
+
+      #if DISABLED(NEWPANEL)
+        #define BEEPER_PIN         33
+      #endif
+
+    #endif
+
+    #if DISABLED(NEWPANEL)
+      // Buttons attached to a shift register
+      // Not wired yet
+      //#define SHIFT_CLK          38
+      //#define SHIFT_LD           42
+      //#define SHIFT_OUT          40
+      //#define SHIFT_EN           17
+    #endif
+
+  #endif
+
+  //
+  // LCD Display input pins
+  //
+  #if ENABLED(NEWPANEL)
+
+    #if ENABLED(REPRAP_DISCOUNT_SMART_CONTROLLER)
+
+      #define BEEPER_PIN           37
+
+      #if ENABLED(CR10_STOCKDISPLAY)
+        // TO TEST
+        // #define BTN_EN1         17
+        // #define BTN_EN2         23
+      #else
+        #define BTN_EN1            31
+        #define BTN_EN2            33
+      #endif
+
+      #define BTN_ENC              35
+      #ifndef SD_DETECT_PIN
+        #define SD_DETECT_PIN      49
+      #endif
+      #define KILL_PIN             41
+
+      #if ENABLED(BQ_LCD_SMART_CONTROLLER)
+        // TO TEST
+        // #define LCD_BACKLIGHT_PIN 39
+      #endif
+
+    #elif ENABLED(REPRAPWORLD_GRAPHICAL_LCD)
+
+      // TO TEST
+      // #define BTN_EN1           56     // Mega/Due:64 - AGCM4:56
+      // #define BTN_EN2           72     // Mega/Due:59 - AGCM4:72
+      // #define BTN_ENC           55
+      // #define SD_DETECT_PIN     42
+
+    #elif ENABLED(LCD_I2C_PANELOLU2)
+
+      // TO TEST
+      // #define BTN_EN1           47
+      // #define BTN_EN2           43
+      // #define BTN_ENC           32
+      // #define LCD_SDSS          SDSS
+      // #define KILL_PIN          41
+
+    #elif ENABLED(LCD_I2C_VIKI)
+
+      // TO TEST
+      // #define BTN_EN1           40   // http://files.panucatt.com/datasheets/viki_wiring_diagram.pdf explains 40/42.
+      // #define BTN_EN2           42
+      // #define BTN_ENC           -1
+
+      // #define LCD_SDSS SDSS
+      // #define SD_DETECT_PIN     49
+
+    #elif ANY(VIKI2, miniVIKI)
+
+      // TO TEST
+      // #define DOGLCD_CS         45
+      // #define DOGLCD_A0         44
+      // #define LCD_SCREEN_ROT_180
+
+      // #define BEEPER_PIN        33
+      // #define STAT_LED_RED_PIN  32
+      // #define STAT_LED_BLUE_PIN 35
+
+      // #define BTN_EN1           22
+      // #define BTN_EN2            7
+      // #define BTN_ENC           39
+
+      // #define SD_DETECT_PIN     -1   // Pin 49 for display SD interface, 72 for easy adapter board
+      // #define KILL_PIN          31
+
+    #elif ENABLED(ELB_FULL_GRAPHIC_CONTROLLER)
+
+      // TO TEST
+      // #define DOGLCD_CS         29
+      // #define DOGLCD_A0         27
+
+      // #define BEEPER_PIN        23
+      // #define LCD_BACKLIGHT_PIN 33
+
+      // #define BTN_EN1           35
+      // #define BTN_EN2           37
+      // #define BTN_ENC           31
+
+      // #define LCD_SDSS          SDSS
+      // #define SD_DETECT_PIN     49
+      // #define KILL_PIN          41
+
+    #elif EITHER(MKS_MINI_12864, FYSETC_MINI_12864)
+
+      // TO TEST
+      //#define BEEPER_PIN         37
+      //#define BTN_ENC            35
+      //#define SD_DETECT_PIN      49
+
+      //#ifndef KILL_PIN
+      //  #define KILL_PIN         41
+      //#endif
+
+      #if ENABLED(MKS_MINI_12864)   // Added in Marlin 1.1.6
+
+        // TO TEST
+        // #define DOGLCD_A0       27
+        // #define DOGLCD_CS       25
+
+        // GLCD features
+        // Uncomment screen orientation
+        // #define LCD_SCREEN_ROT_90
+        // #define LCD_SCREEN_ROT_180
+        // #define LCD_SCREEN_ROT_270
+
+        // not connected to a pin
+        // #define LCD_BACKLIGHT_PIN 57    // backlight LED on A11/D? (Mega/Due:65 - AGCM4:57)
+
+        // #define BTN_EN1         31
+        // #define BTN_EN2         33
+
+      #elif ENABLED(FYSETC_MINI_12864)
+
+        // From https://wiki.fysetc.com/Mini12864_Panel/?fbclid=IwAR1FyjuNdVOOy9_xzky3qqo_WeM5h-4gpRnnWhQr_O1Ef3h0AFnFXmCehK8
+
+        // TO TEST
+        // #define DOGLCD_A0       16
+        // #define DOGLCD_CS       17
+
+        // #define BTN_EN1         33
+        // #define BTN_EN2         31
+
+        //#define FORCE_SOFT_SPI    // Use this if default of hardware SPI causes display problems
+                                    //   results in LCD soft SPI mode 3, SD soft SPI mode 0
+
+        // #define LCD_RESET_PIN   23   // Must be high or open for LCD to operate normally.
+
+        #if EITHER(FYSETC_MINI_12864_1_2, FYSETC_MINI_12864_2_0)
+          #ifndef RGB_LED_R_PIN
+            // TO TEST
+            // #define RGB_LED_R_PIN 25
+          #endif
+          #ifndef RGB_LED_G_PIN
+            // TO TEST
+            // #define RGB_LED_G_PIN 27
+          #endif
+          #ifndef RGB_LED_B_PIN
+            // TO TEST
+            // #define RGB_LED_B_PIN 29
+          #endif
+        #elif ENABLED(FYSETC_MINI_12864_2_1)
+          // TO TEST
+          // #define NEOPIXEL_PIN    25
+        #endif
+
+      #endif
+
+    #elif ENABLED(MINIPANEL)
+
+      // TO TEST
+      // #define BEEPER_PIN        42
+      // not connected to a pin
+      // #define LCD_BACKLIGHT_PIN 57    // backlight LED on A11/D? (Mega/Due:65 - AGCM4:57)
+
+      // #define DOGLCD_A0         44
+      // #define DOGLCD_CS         58    // Mega/Due:66 - AGCM4:58
+
+      // GLCD features
+      // Uncomment screen orientation
+      // #define LCD_SCREEN_ROT_90
+      // #define LCD_SCREEN_ROT_180
+      // #define LCD_SCREEN_ROT_270
+
+      // #define BTN_EN1           40
+      // #define BTN_EN2           55    // Mega/Due:63 - AGCM4:55
+      // #define BTN_ENC           72    // Mega/Due:59 - AGCM4:72
+
+      // #define SD_DETECT_PIN     49
+      // #define KILL_PIN          56    // Mega/Due:64 - AGCM4:56
+
+    #elif ENABLED(ZONESTAR_LCD)
+
+      // TO TEST
+      // #define ADC_KEYPAD_PIN    12
+
+    #elif ENABLED(AZSMZ_12864)
+
+      // TO TEST
+
+    #else
+
+      // Beeper on AUX-4
+      // #define BEEPER_PIN        33
+
+      // Buttons are directly attached to AUX-2
+      #if ENABLED(REPRAPWORLD_KEYPAD)
+        // TO TEST
+        // #define SHIFT_OUT       40
+        // #define SHIFT_CLK       44
+        // #define SHIFT_LD        42
+        // #define BTN_EN1         56    // Mega/Due:64 - AGCM4:56
+        // #define BTN_EN2         72    // Mega/Due:59 - AGCM4:72
+        // #define BTN_ENC         55    // Mega/Due:63 - AGCM4:55
+      #elif ENABLED(PANEL_ONE)
+        // TO TEST
+        // #define BTN_EN1         72    // AUX2 PIN 3 (Mega/Due:59 - AGCM4:72)
+        // #define BTN_EN2         55    // AUX2 PIN 4 (Mega/Due:63 - AGCM4:55)
+        // #define BTN_ENC         49    // AUX3 PIN 7
+      #else
+        // TO TEST
+        // #define BTN_EN1         37
+        // #define BTN_EN2         35
+        // #define BTN_ENC         31
+      #endif
+
+      #if ENABLED(G3D_PANEL)
+        // TO TEST
+        // #define SD_DETECT_PIN   49
+        // #define KILL_PIN        41
+      #endif
+
+    #endif
+  #endif // NEWPANEL
+
+#endif // HAS_SPI_LCD
+
+//
+// SD Support
+//
+#ifndef SDCARD_CONNECTION
+  #define SDCARD_CONNECTION ONBOARD
+#endif
+
+#if SD_CONNECTION_IS(ONBOARD)
+  #undef SDSS
+  #define SDSS             83
+  #undef SD_DETECT_PIN
+  #define SD_DETECT_PIN    95
+#endif
diff --git a/buildroot/share/tests/SAMD51_grandcentral_m4-tests b/buildroot/share/tests/SAMD51_grandcentral_m4-tests
index 898a58560..f7157b1ed 100644
--- a/buildroot/share/tests/SAMD51_grandcentral_m4-tests
+++ b/buildroot/share/tests/SAMD51_grandcentral_m4-tests
@@ -6,5 +6,12 @@
 # exit on first failure
 set -e
 
+#
+# Build with the default configurations
+#
+restore_configs
+opt_set MOTHERBOARD BOARD_AGCM4_RAMPS_144
+exec_test $1 $2 "Build Grand Central M4 Default Configuration"
+
 # clean up
 restore_configs