feature: add esp32flash flash method for esp32s3/esp32c3/esp32/esp8266

This adds usage of the new espflash package to perform flashing on
ESP32, ESP32S3, ESP32C3, & ESP8266 boards. This means that you no longer
have to install esptool.py in order to flash ESP32 based boards.

Signed-off-by: deadprogram <ron@hybridgroup.com>

go.mod

@@ -13,11 +13,12 @@ require (
 	github.com/mattn/go-tty v0.0.4
 	github.com/sigurn/crc16 v0.0.0-20211026045750-20ab5afb07e3
 	github.com/tetratelabs/wazero v1.6.0
-	go.bug.st/serial v1.6.0
+	go.bug.st/serial v1.6.2
 	golang.org/x/net v0.35.0
 	golang.org/x/sys v0.30.0
 	golang.org/x/tools v0.30.0
 	gopkg.in/yaml.v2 v2.4.0
+	tinygo.org/x/espflash v0.1.0
 	tinygo.org/x/go-llvm v0.0.0-20250422114502-b8f170971e74
 )
 

go.sum

@@ -33,8 +33,8 @@ github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcU
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/tetratelabs/wazero v1.6.0 h1:z0H1iikCdP8t+q341xqepY4EWvHEw8Es7tlqiVzlP3g=
 github.com/tetratelabs/wazero v1.6.0/go.mod h1:0U0G41+ochRKoPKCJlh0jMg1CHkyfK8kDqiirMmKY8A=
-go.bug.st/serial v1.6.0 h1:mAbRGN4cKE2J5gMwsMHC2KQisdLRQssO9WSM+rbZJ8A=
-go.bug.st/serial v1.6.0/go.mod h1:UABfsluHAiaNI+La2iESysd9Vetq7VRdpxvjx7CmmOE=
+go.bug.st/serial v1.6.2 h1:kn9LRX3sdm+WxWKufMlIRndwGfPWsH1/9lCWXQCasq8=
+go.bug.st/serial v1.6.2/go.mod h1:UABfsluHAiaNI+La2iESysd9Vetq7VRdpxvjx7CmmOE=
 golang.org/x/mod v0.23.0 h1:Zb7khfcRGKk+kqfxFaP5tZqCnDZMjC5VtUBs87Hr6QM=
 golang.org/x/mod v0.23.0/go.mod h1:6SkKJ3Xj0I0BrPOZoBy3bdMptDDU9oJrpohJ3eWZ1fY=
 golang.org/x/net v0.35.0 h1:T5GQRQb2y08kTAByq9L4/bz8cipCdA8FbRTXewonqY8=
@@ -58,5 +58,7 @@ gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+tinygo.org/x/espflash v0.1.0 h1:3OsU8BwQ8glikAY9J0OLWOYpP3baef/OpW5BqjPu+MU=
+tinygo.org/x/espflash v0.1.0/go.mod h1:n4sWxsjN4wjHN1lKfEYjXke6/eSeLTq/lRRLJS5FNfg=
 tinygo.org/x/go-llvm v0.0.0-20250422114502-b8f170971e74 h1:ovavgTdIBWCH8YWlcfq9gkpoyT1+IxMKSn+Df27QwE8=
 tinygo.org/x/go-llvm v0.0.0-20250422114502-b8f170971e74/go.mod h1:GFbusT2VTA4I+l4j80b17KFK+6whv69Wtny5U+T8RR0=

main.go

@@ -32,6 +32,7 @@ import (
 	"github.com/tinygo-org/tinygo/goenv"
 	"github.com/tinygo-org/tinygo/loader"
 	"golang.org/x/tools/go/buildutil"
+	"tinygo.org/x/espflash"
 	"tinygo.org/x/go-llvm"
 
 	"go.bug.st/serial"
@@ -385,6 +386,8 @@ func Flash(pkgName, port, outpath string, options *compileopts.Options) error {
 		fileExt = ".hex"
 	case "bmp":
 		fileExt = ".elf"
+	case "esp32flash":
+		fileExt = ".bin"
 	case "native":
 		return errors.New("unknown flash method \"native\" - did you miss a -target flag?")
 	default:
@@ -519,6 +522,15 @@ func Flash(pkgName, port, outpath string, options *compileopts.Options) error {
 		if err != nil {
 			return &commandError{"failed to flash", result.Binary, err}
 		}
+	case "esp32flash":
+		port, err := getDefaultPort(port, config.Target.SerialPort)
+		if err != nil {
+			return &commandError{"failed to find port", port, err}
+		}
+
+		if err := flashBinUsingEsp32(port, result.Binary, config.Options); err != nil {
+			return &commandError{"failed to flash", result.Binary, err}
+		}
 	default:
 		return fmt.Errorf("unknown flash method: %s", flashMethod)
 	}
@@ -1019,6 +1031,43 @@ func flashHexUsingMSD(volumes []string, tmppath string, options *compileopts.Opt
 	return errors.New("unable to locate any volume: [" + strings.Join(volumes, ",") + "]")
 }
 
+func flashBinUsingEsp32(port, tmppath string, options *compileopts.Options) error {
+	flasher, err := espflash.NewFlasher(port, nil)
+	if err != nil {
+		return err
+	}
+	defer flasher.Close()
+
+	chipName := flasher.ChipName()
+	fmt.Printf("Connected to %s\n", chipName)
+
+	offset := uint32(0x0)
+	if chipName == "ESP32" {
+		offset = 0x1000
+	}
+
+	// Read the firmware binary
+	data, err := os.ReadFile(tmppath)
+	if err != nil {
+		return err
+	}
+
+	// Flash with progress reporting
+	err = flasher.FlashImage(data, offset, func(current, total int) {
+		fmt.Printf("\rFlashing: %d/%d bytes (%.0f%%)", current, total,
+			float64(current)/float64(total)*100)
+	})
+	if err != nil {
+		return err
+	}
+	fmt.Println()
+
+	// Reset the device to run the new firmware
+	flasher.Reset()
+
+	return nil
+}
+
 type mountPoint struct {
 	name string
 	path string