flashing: introduce flash method 'esp32jtag' for esp32c3/esp32s3 targets

go.mod

@@ -13,18 +13,17 @@ 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 v1.6.2
+	go.bug.st/serial v1.6.4
 	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 v0.2.0
+	tinygo.org/x/espflash v0.3.0
 	tinygo.org/x/go-llvm v0.0.0-20250422114502-b8f170971e74
 )
 
 require (
 	github.com/creack/goselect v0.1.2 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/stretchr/testify v1.8.4 // indirect
 	golang.org/x/text v0.22.0 // indirect
 )

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 v1.6.2 h1:kn9LRX3sdm+WxWKufMlIRndwGfPWsH1/9lCWXQCasq8=
-go.bug.st/serial v1.6.2/go.mod h1:UABfsluHAiaNI+La2iESysd9Vetq7VRdpxvjx7CmmOE=
+go.bug.st/serial v1.6.4 h1:7FmqNPgVp3pu2Jz5PoPtbZ9jJO5gnEnZIvnI1lzve8A=
+go.bug.st/serial v1.6.4/go.mod h1:nofMJxTeNVny/m6+KaafC6vJGj3miwQZ6vW4BZUGJPI=
 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=
@@ -58,7 +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 v0.2.0 h1:sHDeMVaiJ0kEosCYgkiAHjSCV9+/mgQZMKy7nOXWVoQ=
-tinygo.org/x/espflash v0.2.0/go.mod h1:n4sWxsjN4wjHN1lKfEYjXke6/eSeLTq/lRRLJS5FNfg=
+tinygo.org/x/espflash v0.3.0 h1:uhTOWZb1FyQ4MZTZWORh/bOLFQfaFr2nuM9t3pJExRM=
+tinygo.org/x/espflash v0.3.0/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

@@ -32,7 +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/espflash/pkg/espflash"
 	"tinygo.org/x/go-llvm"
 
 	"go.bug.st/serial"
@@ -386,7 +386,7 @@ func Flash(pkgName, port, outpath string, options *compileopts.Options) error {
 		fileExt = ".hex"
 	case "bmp":
 		fileExt = ".elf"
-	case "esp32flash":
+	case "esp32flash", "esp32jtag":
 		fileExt = ".bin"
 	case "native":
 		return errors.New("unknown flash method \"native\" - did you miss a -target flag?")
@@ -528,7 +528,16 @@ func Flash(pkgName, port, outpath string, options *compileopts.Options) error {
 			return &commandError{"failed to find port", port, err}
 		}
 
-		if err := flashBinUsingEsp32(port, result.Binary, config.Options); err != nil {
+		if err := flashBinUsingEsp32(port, classicReset, result.Binary, config.Options); err != nil {
+			return &commandError{"failed to flash", result.Binary, err}
+		}
+	case "esp32jtag":
+		port, err := getDefaultPort(port, config.Target.SerialPort)
+		if err != nil {
+			return &commandError{"failed to find port", port, err}
+		}
+
+		if err := flashBinUsingEsp32(port, jtagReset, result.Binary, config.Options); err != nil {
 			return &commandError{"failed to flash", result.Binary, err}
 		}
 	default:
@@ -1031,8 +1040,20 @@ 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)
+const (
+	classicReset = "classic"
+	jtagReset    = "jtag"
+)
+
+func flashBinUsingEsp32(port, resetMode, tmppath string, options *compileopts.Options) error {
+	var opts *espflash.FlasherOptions
+	// On Windows, we have to explicitly specify the reset mode to use USB JTAG.
+	if runtime.GOOS == "windows" && resetMode == jtagReset {
+		opts = espflash.DefaultOptions()
+		opts.ResetMode = espflash.ResetUSBJTAG
+	}
+
+	flasher, err := espflash.NewFlasher(port, opts)
 	if err != nil {
 		return err
 	}

targets/esp32c3.json

@@ -13,7 +13,7 @@
 		"src/device/esp/esp32c3.S"
 	],
 	"binary-format": "esp32c3",
-	"flash-method": "esp32flash",
+	"flash-method": "esp32jtag",
 	"serial-port": ["303a:1001"],
 	"openocd-interface": "esp_usb_jtag",
 	"openocd-target": "esp32c3",

targets/esp32s3.json

@@ -15,7 +15,7 @@
 		"src/internal/task/task_stack_esp32.S"
 	],
 	"binary-format": "esp32s3",
-	"flash-method": "esp32flash",
+	"flash-method": "esp32jtag",
 	"emulator": "qemu-system-xtensa -machine esp32 -nographic -drive file={img},if=mtd,format=raw",
 	"gdb": ["xtensa-esp32-elf-gdb"]
 }