diff --git a/app/commands.hh b/app/commands.hh
index bf23ca5..86bfd80 100644
--- a/app/commands.hh
+++ b/app/commands.hh
@@ -5,6 +5,7 @@
 #pragma once
 
 #include "flash/flash.hh"
+#include "embeddedpp/gpio.hh"
 #include "visuals/progressbar.hh"
 #include "visuals/throughput.hh"
 #include <fstream>
@@ -262,4 +263,23 @@ struct LoadFile : public Commands<T> {
   }
 };
 
+template <typename T>
+  requires embeddedpp::Gpio<T>
+struct GpioWrite {
+  T& gpio;
+  uint8_t pin;
+  bool value;
+
+  GpioWrite(T& gpio, uint8_t pin, bool value) : gpio(gpio), pin(pin), value(value) {}
+
+  int run() {
+    if (is_error(gpio.set_pin(pin, value))) {
+      std::println("GPIO write failed");
+      return 1;
+    }
+    std::println("GPIO{} = {}", pin, value ? 1 : 0);
+    return 0;
+  }
+};
+
 }  // namespace commands
diff --git a/app/main.cc b/app/main.cc
index 046d468..dd73453 100644
--- a/app/main.cc
+++ b/app/main.cc
@@ -12,6 +12,7 @@
 
 #include "ftdi/ftdi.hh"
 #include "ftdi/spi_host.hh"
+#include "ftdi/gpio.hh"
 #include "flash/flash.hh"
 #include "commands.hh"
 #include "ftdi/log.hh"
@@ -41,10 +42,9 @@ static std::vector<ftdi::DeviceInfo> scan() {
 }
 
 static std::unique_ptr<argparse::ArgumentParser>
-new_flash_command(const std::string& name, const std::string& desc) {
+new_command(const std::string& name, const std::string& desc) {
   auto cmd = std::make_unique<argparse::ArgumentParser>(name);
   cmd->add_description(desc);
-  cmd->add_argument("--interface", "-i").help("One of [spi, i2c, gpio]");
   cmd->add_argument("--traces", "-t")
       .help("Enable ftdi traces")
       .default_value(false)
@@ -52,6 +52,12 @@ new_flash_command(const std::string& name, const std::string& desc) {
   cmd->add_argument("--ftdi")
       .default_value(std::string("FT4222"))
       .help("Filter ftdi chips connected to USB");
+  return cmd;
+}
+
+static std::unique_ptr<argparse::ArgumentParser>
+new_flash_command(const std::string& name, const std::string& desc) {
+  auto cmd = new_command(name, desc);
   cmd->add_argument("--clock")
       .default_value(std::size_t{15000000})
       .help("The spi clock speed in Hz.")
@@ -79,6 +85,22 @@ handle_flash_command(std::unique_ptr<argparse::ArgumentParser>& cmd) {
   exit(0);
 }
 
+static std::optional<ftdi::Gpio>
+handle_gpio_command(std::unique_ptr<argparse::ArgumentParser>& cmd) {
+  auto ftdi_filter = cmd->get<std::string>("--ftdi");
+  auto devices     = scan();
+  auto filtered    = ftdi::DeviceInfo::filter_by_description(devices, ftdi_filter);
+  if (filtered.empty()) {
+    std::print("No {} ftdi found.\n", ftdi_filter);
+    exit(0);
+  }
+  if (auto opt = ftdi::Gpio::from_device_info(filtered[0])) {
+    return opt;
+  }
+  std::println("Can't open GPIO.");
+  exit(0);
+}
+
 int main(int argc, char* argv[]) {
   std::map<std::string, Action> commands;
 
@@ -204,6 +226,19 @@ int main(int argc, char* argv[]) {
     return 0;
   };
 
+  auto gpio_write_cmd = new_command("gpio-write", "Write a value to an FTDI GPIO pin.");
+  gpio_write_cmd->add_argument("pin").help("GPIO pin number (0-3)").required().scan<'d', int>();
+  gpio_write_cmd->add_argument("value").help("Value to write (0 or 1)").required().scan<'d', int>();
+  program.add_subparser(*gpio_write_cmd);
+  commands["gpio-write"] = [&]() -> int {
+    auto pin   = static_cast<uint8_t>(gpio_write_cmd->get<int>("pin"));
+    auto value = gpio_write_cmd->get<int>("value") != 0;
+    auto gpio  = handle_gpio_command(gpio_write_cmd);
+    commands::GpioWrite(*gpio, pin, value).run();
+    gpio->close();
+    return 0;
+  };
+
   if (argc == 1) {
     std::cout << program;  // This prints the auto-generated help
     return 0;
diff --git a/lib/embeddedpp/CMakeLists.txt b/lib/embeddedpp/CMakeLists.txt
index f2185d2..84d14da 100644
--- a/lib/embeddedpp/CMakeLists.txt
+++ b/lib/embeddedpp/CMakeLists.txt
@@ -10,6 +10,7 @@ target_sources(embeddedpp
         BASE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}
         FILES
             spi.hh
+            gpio.hh
             helpers.hh
 )
 
diff --git a/lib/embeddedpp/gpio.hh b/lib/embeddedpp/gpio.hh
new file mode 100644
index 0000000..b81af9b
--- /dev/null
+++ b/lib/embeddedpp/gpio.hh
@@ -0,0 +1,19 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <concepts>
+#include <cstdint>
+#include "helpers.hh"
+
+namespace embeddedpp {
+
+template <typename T>
+concept Gpio = requires(T t, uint8_t pin, bool value) {
+  { t.set_pin(pin, value) } -> std::same_as<Status>;
+  { t.get_pin(pin) } -> std::same_as<Result<bool>>;
+};
+
+}  // namespace embeddedpp
diff --git a/lib/ftdi/CMakeLists.txt b/lib/ftdi/CMakeLists.txt
index 0438cf3..a674556 100644
--- a/lib/ftdi/CMakeLists.txt
+++ b/lib/ftdi/CMakeLists.txt
@@ -7,12 +7,14 @@ add_library(ftdipp)
 target_sources(ftdipp
     PRIVATE
         spi_host.cc
+        gpio.cc
     PUBLIC
         FILE_SET HEADERS
         BASE_DIRS ${CMAKE_CURRENT_SOURCE_DIR}
         FILES
             ftdi.hh
             spi_host.hh
+            gpio.hh
             log.hh
 )
 
diff --git a/lib/ftdi/gpio.cc b/lib/ftdi/gpio.cc
new file mode 100644
index 0000000..2454ce1
--- /dev/null
+++ b/lib/ftdi/gpio.cc
@@ -0,0 +1,150 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#include "gpio.hh"
+#include "libft4222.h"
+#include "libmpsse_spi.h"
+#include "ftd2xx.h"
+#include <iostream>
+#include <format>
+#include <print>
+
+namespace ftdi {
+
+void Gpio::close() {
+  if (mpsse) {
+    SPI_CloseChannel(handle);
+    Cleanup_libMPSSE();
+  } else {
+    FT4222_UnInitialize(handle);
+    FT_Close(handle);
+  }
+}
+
+embeddedpp::Result<bool> Gpio::get_pin(uint8_t pin) {
+  uint8_t mask = static_cast<uint8_t>(1 << pin);
+  if (mpsse) {
+    if (pin > 7) {
+      std::cerr << std::format("gpio pin must be 0-7\n");
+      return embeddedpp::Code::InvalidArgument;
+    }
+    uint8_t value    = 0;
+    FT_STATUS status = FT_ReadGPIO(handle, &value);
+    return (value & mask) == mask;
+  }
+
+  if (pin > 3) {
+    std::cerr << std::format("gpio pin must be 0-3\n");
+    return embeddedpp::Code::InvalidArgument;
+  }
+
+  GPIO_Port port = static_cast<GPIO_Port>(pin);
+  BOOL enable;
+  FT4222_STATUS status = FT4222_GPIO_Read(handle, port, &enable);
+  if (FT4222_OK != status) {
+    std::cerr << std::format("FT4222_GPIO_Read: {}\n", status);
+    return embeddedpp::Code::Generic;
+  }
+  return enable > 0;
+}
+
+embeddedpp::Status Gpio::set_pin(uint8_t pin, bool en) {
+  if (mpsse) {
+    if (pin > 7) {
+      std::cerr << std::format("gpio pin must be 0-7\n");
+      return embeddedpp::Code::InvalidArgument;
+    }
+    uint8_t value = 0;
+    FT_STATUS status;
+    status = FT_ReadGPIO(handle, &value);
+    if (en) {
+      value |= static_cast<uint8_t>(1 << pin);
+    } else {
+      value &= static_cast<uint8_t>(~(1 << pin));
+    }
+    status = FT_WriteGPIO(handle, 0xff, value);
+    if (FT_OK != status) {
+      std::cerr << std::format("FT_WriteGPIO: {}\n", status);
+      return embeddedpp::Code::Generic;
+    }
+    return true;
+  }
+
+  if (pin > 3) {
+    std::cerr << std::format("gpio pin must be 0-3\n");
+    return embeddedpp::Code::InvalidArgument;
+  }
+
+  GPIO_Port port       = static_cast<GPIO_Port>(pin);
+  FT4222_STATUS status = FT4222_GPIO_Write(handle, port, en ? TRUE : FALSE);
+  if (FT4222_OK != status) {
+    std::cerr << std::format("FT4222_GPIO_Write: {}\n", status);
+    return embeddedpp::Code::Generic;
+  }
+  return embeddedpp::Code::Ok;
+}
+
+static std::optional<Gpio> new_ft4222_gpio(DeviceInfo& device) {
+  FT_HANDLE handle;
+  FT_STATUS res = FT_OpenEx((PVOID)(uintptr_t)device.loc_id, FT_OPEN_BY_LOCATION, &handle);
+  if (res != FT_OK) {
+    std::cerr << std::format("Gpio Open:{}\n", res);
+    return std::nullopt;
+  }
+
+  // Initialize all four GPIO pins as outputs.
+  GPIO_Dir dir[4]      = {GPIO_OUTPUT, GPIO_OUTPUT, GPIO_OUTPUT, GPIO_OUTPUT};
+  FT4222_STATUS status = FT4222_GPIO_Init(handle, dir);
+  if (FT4222_OK != status) {
+    std::cerr << std::format("FT4222_GPIO_Init:{}\n", status);
+    FT_Close(handle);
+    return std::nullopt;
+  }
+
+  return std::optional<Gpio>{handle};
+}
+
+static std::optional<Gpio> new_ft2232_gpio(DeviceInfo& device) {
+  FT_HANDLE handle;
+  FT_STATUS res;
+  const uint32_t channel = 0;
+  Init_libMPSSE();
+
+  std::println("Opening {}, channel {}", device.serial_number, channel);
+  res = SPI_OpenChannel(channel, &handle);
+  if (res != FT_OK) {
+    std::cerr << std::format("Gpio Open:{}\n", res);
+    Cleanup_libMPSSE();
+    return std::nullopt;
+  }
+
+  ChannelConfig config = {.ClockRate     = 1000000,  // 1MHz
+                          .LatencyTimer  = 2,
+                          .configOptions = SPI_CONFIG_OPTION_MODE0 | SPI_CONFIG_OPTION_CS_DBUS3 |
+                                           SPI_CONFIG_OPTION_CS_ACTIVELOW};
+  res                  = SPI_InitChannel(handle, &config);
+  if (res != FT_OK) {
+    std::cerr << std::format("Spi InitChannel: {}\n", res);
+    return std::nullopt;
+  }
+
+  return std::optional<Gpio>{Gpio(handle, true)};
+}
+
+std::optional<Gpio> Gpio::from_device_info(DeviceInfo& device) {
+  switch (device.type) {
+    case DeviceType::Ftdi_2232h:
+      return new_ft2232_gpio(device);
+    case DeviceType::Ftdi_4222h_0:
+    case DeviceType::Ftdi_4222h_1_2:
+    case DeviceType::Ftdi_4222h_3:
+      return new_ft4222_gpio(device);
+    default:
+      break;
+  }
+  std::cerr << std::format("Gpio: device not supported {}\n", device);
+  return std::nullopt;
+}
+
+};  // namespace ftdi
diff --git a/lib/ftdi/gpio.hh b/lib/ftdi/gpio.hh
new file mode 100644
index 0000000..4aa65ce
--- /dev/null
+++ b/lib/ftdi/gpio.hh
@@ -0,0 +1,32 @@
+// Copyright lowRISC contributors.
+// Licensed under the Apache License, Version 2.0, see LICENSE for details.
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <cstdint>
+#include <optional>
+#include "libft4222.h"
+#include "ftdi.hh"
+#include "embeddedpp/helpers.hh"
+
+namespace ftdi {
+
+class Gpio {
+  FT_HANDLE handle;
+  bool mpsse = false;
+
+ public:
+  explicit Gpio(FT_HANDLE handle) noexcept : handle(handle) {}
+  Gpio(FT_HANDLE handle, bool mpsse) noexcept : handle(handle), mpsse(mpsse) {}
+  ~Gpio() = default;
+
+  void close();
+
+  embeddedpp::Status set_pin(uint8_t pin, bool value);
+  embeddedpp::Result<bool> get_pin(uint8_t pin);
+
+  static std::optional<Gpio> from_device_info(DeviceInfo& device);
+};
+
+}  // namespace ftdi