diff --git a/Makefile b/Makefile
index ad09d9e4..50aa13e0 100644
--- a/Makefile
+++ b/Makefile
@@ -226,6 +226,8 @@ smoketest:
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=stm32f4disco        examples/blinky2
 	@$(MD5SUM) test.hex
+	$(TINYGO) build -size short -o test.hex -target=circuitplay-bluefruit examples/blinky1
+	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.hex -target=circuitplay-express examples/i2s
 	@$(MD5SUM) test.hex
 	$(TINYGO) build -size short -o test.gba -target=gameboy-advance     examples/gba-display
diff --git a/README.md b/README.md
index 56708f00..74d90b6f 100644
--- a/README.md
+++ b/README.md
@@ -46,6 +46,7 @@ You can compile TinyGo programs for microcontrollers, WebAssembly and Linux.
 The following 22 microcontroller boards are currently supported:
 
 * [Adafruit Circuit Playground Express](https://www.adafruit.com/product/3333)
+* [Adafruit Circuit Playground Bluefruit](https://www.adafruit.com/product/4333)
 * [Adafruit Feather M0](https://www.adafruit.com/product/2772)
 * [Adafruit Feather M4](https://www.adafruit.com/product/3857)
 * [Adafruit ItsyBitsy M0](https://www.adafruit.com/product/3727)
diff --git a/builder/build.go b/builder/build.go
index f9577801..fa4c689f 100644
--- a/builder/build.go
+++ b/builder/build.go
@@ -207,7 +207,7 @@ func Build(pkgName, outpath string, config *compileopts.Config, action func(stri
 		} else if outext == ".uf2" {
 			// Get UF2 from the .elf file.
 			tmppath = filepath.Join(dir, "main"+outext)
-			err := convertELFFileToUF2File(executable, tmppath)
+			err := convertELFFileToUF2File(executable, tmppath, config.Target.UF2FamilyID)
 			if err != nil {
 				return err
 			}
diff --git a/builder/uf2.go b/builder/uf2.go
index 3ff0a045..24417a02 100644
--- a/builder/uf2.go
+++ b/builder/uf2.go
@@ -11,26 +11,33 @@ import (
 	"bytes"
 	"encoding/binary"
 	"io/ioutil"
+	"strconv"
 )
 
 // convertELFFileToUF2File converts an ELF file to a UF2 file.
-func convertELFFileToUF2File(infile, outfile string) error {
+func convertELFFileToUF2File(infile, outfile string, uf2FamilyID string) error {
 	// Read the .text segment.
 	targetAddress, data, err := extractROM(infile)
 	if err != nil {
 		return err
 	}
 
-	output, _ := convertBinToUF2(data, uint32(targetAddress))
+	output, _, err := convertBinToUF2(data, uint32(targetAddress), uf2FamilyID)
+	if err != nil {
+		return err
+	}
 	return ioutil.WriteFile(outfile, output, 0644)
 }
 
 // convertBinToUF2 converts the binary bytes in input to UF2 formatted data.
-func convertBinToUF2(input []byte, targetAddr uint32) ([]byte, int) {
+func convertBinToUF2(input []byte, targetAddr uint32, uf2FamilyID string) ([]byte, int, error) {
 	blocks := split(input, 256)
 	output := make([]byte, 0)
 
-	bl := newUF2Block(targetAddr)
+	bl, err := newUF2Block(targetAddr, uf2FamilyID)
+	if err != nil {
+		return nil, 0, err
+	}
 	bl.SetNumBlocks(len(blocks))
 
 	for i := 0; i < len(blocks); i++ {
@@ -41,7 +48,7 @@ func convertBinToUF2(input []byte, targetAddr uint32) ([]byte, int) {
 		bl.IncrementAddress(bl.payloadSize)
 	}
 
-	return output, len(blocks)
+	return output, len(blocks), nil
 }
 
 const (
@@ -65,18 +72,32 @@ type uf2Block struct {
 }
 
 // newUF2Block returns a new uf2Block struct that has been correctly populated
-func newUF2Block(targetAddr uint32) *uf2Block {
+func newUF2Block(targetAddr uint32, uf2FamilyID string) (*uf2Block, error) {
+	var flags uint32
+	var familyID uint32
+	if uf2FamilyID != "" {
+		flags |= flagFamilyIDPresent
+		v, err := strconv.ParseUint(uf2FamilyID, 0, 32)
+		if err != nil {
+			return nil, err
+		}
+		familyID = uint32(v)
+	}
 	return &uf2Block{magicStart0: uf2MagicStart0,
 		magicStart1: uf2MagicStart1,
 		magicEnd:    uf2MagicEnd,
 		targetAddr:  targetAddr,
-		flags:       0x0,
-		familyID:    0x0,
+		flags:       flags,
+		familyID:    familyID,
 		payloadSize: 256,
 		data:        make([]byte, 476),
-	}
+	}, nil
 }
 
+const (
+	flagFamilyIDPresent = 0x00002000
+)
+
 // Bytes converts the uf2Block to a slice of bytes that can be written to file.
 func (b *uf2Block) Bytes() []byte {
 	buf := bytes.NewBuffer(make([]byte, 0, 512))
diff --git a/compileopts/target.go b/compileopts/target.go
index 3bc05da4..2e989ac5 100644
--- a/compileopts/target.go
+++ b/compileopts/target.go
@@ -43,6 +43,7 @@ type TargetSpec struct {
 	FlashMethod      string   `json:"flash-method"`
 	FlashVolume      string   `json:"msd-volume-name"`
 	FlashFilename    string   `json:"msd-firmware-name"`
+	UF2FamilyID      string   `json:"uf2-family-id"`
 	OpenOCDInterface string   `json:"openocd-interface"`
 	OpenOCDTarget    string   `json:"openocd-target"`
 	OpenOCDTransport string   `json:"openocd-transport"`
@@ -109,6 +110,9 @@ func (spec *TargetSpec) copyProperties(spec2 *TargetSpec) {
 	if spec2.FlashFilename != "" {
 		spec.FlashFilename = spec2.FlashFilename
 	}
+	if spec2.UF2FamilyID != "" {
+		spec.UF2FamilyID = spec2.UF2FamilyID
+	}
 	if spec2.OpenOCDInterface != "" {
 		spec.OpenOCDInterface = spec2.OpenOCDInterface
 	}
diff --git a/src/machine/board_circuitplay_bluefruit.go b/src/machine/board_circuitplay_bluefruit.go
new file mode 100644
index 00000000..e33bc81a
--- /dev/null
+++ b/src/machine/board_circuitplay_bluefruit.go
@@ -0,0 +1,73 @@
+// +build circuitplay_bluefruit
+
+package machine
+
+const HasLowFrequencyCrystal = true
+
+// GPIO Pins
+const (
+	D0  = P0_30
+	D1  = P0_14
+	D2  = P0_05
+	D3  = P0_04
+	D4  = P1_02
+	D5  = P1_15
+	D6  = P0_02
+	D7  = P1_06
+	D8  = P0_13
+	D9  = P0_29
+	D10 = P0_03
+	D11 = P1_04
+	D12 = P0_26
+	D13 = P1_14
+)
+
+// Analog Pins
+const (
+	A1 = P0_02
+	A2 = P0_29
+	A3 = P0_03
+	A4 = P0_04
+	A5 = P0_05
+	A6 = P0_30
+	A7 = P0_14
+	A8 = P0_28
+	A9 = P0_31
+)
+
+const (
+	LED       = D13
+	NEOPIXELS = D8
+
+	BUTTONA = D4
+	BUTTONB = D5
+	SLIDER  = D7 // built-in slide switch
+
+	BUTTON  = BUTTONA
+	BUTTON1 = BUTTONB
+
+	LIGHTSENSOR = A8
+	TEMPSENSOR  = A9
+)
+
+// UART0 pins (logical UART1)
+const (
+	UART_TX_PIN = P0_14 // PORTB
+	UART_RX_PIN = P0_30 // PORTB
+)
+
+// I2C pins
+const (
+	SDA_PIN = P0_05 // I2C0 external
+	SCL_PIN = P0_04 // I2C0 external
+
+	SDA1_PIN = P0_00 // I2C1 internal
+	SCL1_PIN = P0_01 // I2C1 internal
+)
+
+// SPI pins (internal flash)
+const (
+	SPI0_SCK_PIN  = P0_19 // SCK
+	SPI0_MOSI_PIN = P0_21 // MOSI
+	SPI0_MISO_PIN = P0_23 // MISO
+)
diff --git a/src/machine/machine_nrf52840.go b/src/machine/machine_nrf52840.go
index e192567d..a9dc60cc 100644
--- a/src/machine/machine_nrf52840.go
+++ b/src/machine/machine_nrf52840.go
@@ -11,6 +11,58 @@ func CPUFrequency() uint32 {
 	return 64000000
 }
 
+// Hardware pins
+const (
+	P0_00 Pin = 0
+	P0_01 Pin = 1
+	P0_02 Pin = 2
+	P0_03 Pin = 3
+	P0_04 Pin = 4
+	P0_05 Pin = 5
+	P0_06 Pin = 6
+	P0_07 Pin = 7
+	P0_08 Pin = 8
+	P0_09 Pin = 9
+	P0_10 Pin = 10
+	P0_11 Pin = 11
+	P0_12 Pin = 12
+	P0_13 Pin = 13
+	P0_14 Pin = 14
+	P0_15 Pin = 15
+	P0_16 Pin = 16
+	P0_17 Pin = 17
+	P0_18 Pin = 18
+	P0_19 Pin = 19
+	P0_20 Pin = 20
+	P0_21 Pin = 21
+	P0_22 Pin = 22
+	P0_23 Pin = 23
+	P0_24 Pin = 24
+	P0_25 Pin = 25
+	P0_26 Pin = 26
+	P0_27 Pin = 27
+	P0_28 Pin = 28
+	P0_29 Pin = 29
+	P0_30 Pin = 30
+	P0_31 Pin = 31
+	P1_00 Pin = 32
+	P1_01 Pin = 33
+	P1_02 Pin = 34
+	P1_03 Pin = 35
+	P1_04 Pin = 36
+	P1_05 Pin = 37
+	P1_06 Pin = 38
+	P1_07 Pin = 39
+	P1_08 Pin = 40
+	P1_09 Pin = 41
+	P1_10 Pin = 42
+	P1_11 Pin = 43
+	P1_12 Pin = 44
+	P1_13 Pin = 45
+	P1_14 Pin = 46
+	P1_15 Pin = 47
+)
+
 // Get peripheral and pin number for this GPIO pin.
 func (p Pin) getPortPin() (*nrf.GPIO_Type, uint32) {
 	if p >= 32 {
diff --git a/targets/circuitplay-bluefruit.json b/targets/circuitplay-bluefruit.json
new file mode 100644
index 00000000..e948115b
--- /dev/null
+++ b/targets/circuitplay-bluefruit.json
@@ -0,0 +1,9 @@
+{
+    "inherits": ["nrf52840"],
+    "build-tags": ["circuitplay_bluefruit"],
+    "flash-method": "msd",
+    "msd-volume-name": "CPLAYBTBOOT",
+    "msd-firmware-name": "firmware.uf2",
+    "uf2-family-id": "0xADA52840",
+    "linkerscript": "targets/circuitplay-bluefruit.ld"
+}
diff --git a/targets/circuitplay-bluefruit.ld b/targets/circuitplay-bluefruit.ld
new file mode 100644
index 00000000..a5befb8c
--- /dev/null
+++ b/targets/circuitplay-bluefruit.ld
@@ -0,0 +1,10 @@
+
+MEMORY
+{
+    FLASH_TEXT (rw) : ORIGIN = 0x00000000+0x26000, LENGTH = 0xED000-0x26000 /* SoftDevice S140. See https://learn.adafruit.com/introducing-the-adafruit-nrf52840-feather/hathach-memory-map. Application starts at 0x26000; user data starts at 0xED000 */
+    RAM (xrw)       : ORIGIN = 0x20004180, LENGTH = 37K
+}
+
+_stack_size = 2K;
+
+INCLUDE "targets/arm.ld"