diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e30311b8bf..118135850e 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -219,6 +219,7 @@ jobs:
         - "sparkfun_redboard_turbo"
         - "sparkfun_samd21_dev"
         - "sparkfun_samd21_mini"
+        - "sparkfun_samd51_thing_plus"
         - "spresense"
         - "stm32f411ce_blackpill"
         - "stm32f411ve_discovery"
diff --git a/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/board.c b/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/board.c
new file mode 100644
index 0000000000..8096b9b8ea
--- /dev/null
+++ b/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/board.c
@@ -0,0 +1,38 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "boards/board.h"
+#include "mpconfigboard.h"
+
+void board_init(void) {
+}
+
+bool board_requests_safe_mode(void) {
+    return false;
+}
+
+void reset_board(void) {
+}
diff --git a/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/mpconfigboard.h b/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/mpconfigboard.h
new file mode 100644
index 0000000000..a5dee295bf
--- /dev/null
+++ b/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/mpconfigboard.h
@@ -0,0 +1,33 @@
+#define MICROPY_HW_BOARD_NAME "SparkFun Thing Plus - SAMD51"
+#define MICROPY_HW_MCU_NAME "samd51j20"
+
+#define CIRCUITPY_MCU_FAMILY samd51
+
+// On-board flash
+#define SPI_FLASH_MOSI_PIN &pin_PA08
+#define SPI_FLASH_MISO_PIN &pin_PA11
+#define SPI_FLASH_SCK_PIN  &pin_PA09
+#define SPI_FLASH_CS_PIN   &pin_PA10
+
+// These are pins not to reset.
+// SPI Data pins
+#define MICROPY_PORT_A (PORT_PA08 | PORT_PA09 | PORT_PA10 | PORT_PA11)
+#define MICROPY_PORT_B (0)
+#define MICROPY_PORT_C (0)
+#define MICROPY_PORT_D (0)
+
+#define BOARD_HAS_CRYSTAL 1
+
+#define DEFAULT_I2C_BUS_SCL (&pin_PA22)
+#define DEFAULT_I2C_BUS_SDA (&pin_PA23)
+
+#define DEFAULT_SPI_BUS_SCK (&pin_PB13)
+#define DEFAULT_SPI_BUS_MOSI (&pin_PB12)
+#define DEFAULT_SPI_BUS_MISO (&pin_PB11)
+
+#define DEFAULT_UART_BUS_RX (&pin_PA13)
+#define DEFAULT_UART_BUS_TX (&pin_PA12)
+
+// USB is always used internally so skip the pin objects for it.
+#define IGNORE_PIN_PA24     1
+#define IGNORE_PIN_PA25     1
diff --git a/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/mpconfigboard.mk b/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/mpconfigboard.mk
new file mode 100644
index 0000000000..13863e565f
--- /dev/null
+++ b/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/mpconfigboard.mk
@@ -0,0 +1,17 @@
+LD_FILE = boards/samd51x20-bootloader-external-flash.ld
+USB_VID = 0x1b4f
+USB_PID = 0x0016 # Used by uf2 bootloader
+USB_PRODUCT = "SparkFun  SAMD51 Thing+"
+USB_MANUFACTURER = "SparkFun Electronics"
+
+CHIP_VARIANT = SAMD51J20A
+CHIP_FAMILY = samd51
+
+SPI_FLASH_FILESYSTEM = 1
+EXTERNAL_FLASH_DEVICE_COUNT = 1
+EXTERNAL_FLASH_DEVICES = AT25SF041A
+LONGINT_IMPL = MPZ
+
+CIRCUITPY_NETWORK = 1
+MICROPY_PY_WIZNET5K = 5500
+CIRCUITPY_PS2IO = 1
diff --git a/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/pins.c b/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/pins.c
new file mode 100644
index 0000000000..a9ac6d98a9
--- /dev/null
+++ b/ports/atmel-samd/boards/sparkfun_samd51_thing_plus/pins.c
@@ -0,0 +1,37 @@
+#include "shared-bindings/board/__init__.h"
+
+STATIC const mp_rom_map_elem_t board_global_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_A0), MP_ROM_PTR(&pin_PA02) },
+    { MP_ROM_QSTR(MP_QSTR_A1), MP_ROM_PTR(&pin_PB08) },
+    { MP_ROM_QSTR(MP_QSTR_A2), MP_ROM_PTR(&pin_PB09) },
+    { MP_ROM_QSTR(MP_QSTR_A3), MP_ROM_PTR(&pin_PA04) },
+    { MP_ROM_QSTR(MP_QSTR_A4), MP_ROM_PTR(&pin_PA05) },
+    { MP_ROM_QSTR(MP_QSTR_A5), MP_ROM_PTR(&pin_PB02) },
+    { MP_ROM_QSTR(MP_QSTR_SCK), MP_ROM_PTR(&pin_PB13) },
+    { MP_ROM_QSTR(MP_QSTR_D24), MP_ROM_PTR(&pin_PB13) },
+    { MP_ROM_QSTR(MP_QSTR_MOSI), MP_ROM_PTR(&pin_PB12) },
+    { MP_ROM_QSTR(MP_QSTR_D23), MP_ROM_PTR(&pin_PB12) },
+    { MP_ROM_QSTR(MP_QSTR_MISO), MP_ROM_PTR(&pin_PB11) },
+    { MP_ROM_QSTR(MP_QSTR_D22), MP_ROM_PTR(&pin_PB11) },
+    { MP_ROM_QSTR(MP_QSTR_RX), MP_ROM_PTR(&pin_PA13) },
+    { MP_ROM_QSTR(MP_QSTR_TX), MP_ROM_PTR(&pin_PA12) },
+    { MP_ROM_QSTR(MP_QSTR_D0), MP_ROM_PTR(&pin_PA13) }, // D0 == RX
+    { MP_ROM_QSTR(MP_QSTR_D1), MP_ROM_PTR(&pin_PA12) }, // D1 == TX
+    { MP_ROM_QSTR(MP_QSTR_D4), MP_ROM_PTR(&pin_PA06) },
+    { MP_ROM_QSTR(MP_QSTR_SDA), MP_ROM_PTR(&pin_PA22) },
+    { MP_ROM_QSTR(MP_QSTR_D20), MP_ROM_PTR(&pin_PA22) },
+    { MP_ROM_QSTR(MP_QSTR_SCL), MP_ROM_PTR(&pin_PA23) },
+    { MP_ROM_QSTR(MP_QSTR_D21), MP_ROM_PTR(&pin_PA23) },
+    { MP_ROM_QSTR(MP_QSTR_D5), MP_ROM_PTR(&pin_PA15) },
+    { MP_ROM_QSTR(MP_QSTR_D6), MP_ROM_PTR(&pin_PA20) },
+    { MP_ROM_QSTR(MP_QSTR_D9), MP_ROM_PTR(&pin_PA07) },
+    { MP_ROM_QSTR(MP_QSTR_D10), MP_ROM_PTR(&pin_PA18) },
+    { MP_ROM_QSTR(MP_QSTR_D11), MP_ROM_PTR(&pin_PA16) },
+    { MP_ROM_QSTR(MP_QSTR_D12), MP_ROM_PTR(&pin_PA19) },
+    { MP_ROM_QSTR(MP_QSTR_D13), MP_ROM_PTR(&pin_PA17) },
+    { MP_ROM_QSTR(MP_QSTR_LED), MP_ROM_PTR(&pin_PA17) },
+    { MP_ROM_QSTR(MP_QSTR_I2C), MP_ROM_PTR(&board_i2c_obj) },
+    { MP_ROM_QSTR(MP_QSTR_SPI), MP_ROM_PTR(&board_spi_obj) },
+    { MP_ROM_QSTR(MP_QSTR_UART), MP_ROM_PTR(&board_uart_obj) },
+};
+MP_DEFINE_CONST_DICT(board_module_globals, board_global_dict_table);
diff --git a/supervisor/shared/external_flash/devices.h b/supervisor/shared/external_flash/devices.h
index 55a52b40d3..50263e5d6f 100644
--- a/supervisor/shared/external_flash/devices.h
+++ b/supervisor/shared/external_flash/devices.h
@@ -105,6 +105,25 @@ typedef struct {
     .single_status_byte = false, \
 }
 
+// Settings for the Adesto Tech AT25SF041 1MiB SPI flash. It's on the SparkFun
+// SAMD51 Thing Plus board
+// Datasheet: https://www.adestotech.com/wp-content/uploads/DS-AT25SF041_044.pdf
+#define AT25SF041A {\
+    .total_size = (1 << 19), /* 512 KiB */ \
+    .start_up_time_us = 10000, \
+    .manufacturer_id = 0x1f, \
+    .memory_type = 0x84, \
+    .capacity = 0x01, \
+    .max_clock_speed_mhz = 85, \
+    .quad_enable_bit_mask = 0x00, \
+    .has_sector_protection = false, \
+    .supports_fast_read = true, \
+    .supports_qspi = false, \
+    .supports_qspi_writes = false, \
+    .write_status_register_split = false, \
+    .single_status_byte = false, \
+}
+
 // Settings for the Gigadevice GD25Q16C 2MiB SPI flash.
 // Datasheet: http://www.gigadevice.com/datasheet/gd25q16c/
 #define GD25Q16C {\