diff --git a/src/fx2_ll.cpp b/src/fx2_ll.cpp
index f937040..afd911e 100644
--- a/src/fx2_ll.cpp
+++ b/src/fx2_ll.cpp
@@ -14,7 +14,7 @@
 #include "display.hpp"
 #include "fx2_ll.hpp"
 #include "ihexParser.hpp"
-
+#include "progressBar.hpp"
 
 #define FX2_FIRM_LOAD          0xA0
 #define FX2_GCR_CPUCS          0xe600
@@ -42,27 +42,36 @@ FX2_ll::FX2_ll(uint16_t uninit_vid, uint16_t uninit_pid,
 				throw std::runtime_error("claim interface failed");
 			}
 			/* load firmware */
-			load_firmware(firmware_path);
+			if (!load_firmware(firmware_path)) {
+				libusb_close(dev_handle);
+				libusb_exit(usb_ctx);
+				throw std::runtime_error("fx2 firmware load failed");
+			}
 			close();
 			reenum = true;
 		}
 	}
 
 	/* try to open an already init device
-	 * since fx2 may be not immediately ready
+	 * since fx2 may be not immediatly ready
 	 * retry with a delay
 	 */
+	ProgressBar progress("Waiting reload", 100, 50, false);
 	int timeout = 100;
 	do {
 		dev_handle = libusb_open_device_with_vid_pid(usb_ctx,
 				vid, pid);
 		timeout--;
+		progress.display(100-timeout);
 		if (!dev_handle)
 			sleep(1);
 	} while (!dev_handle && timeout > 0 && reenum);
 
-	if (!dev_handle)
+	if (!dev_handle) {
+		progress.fail();
 		throw std::runtime_error("FX2: fail to open device");
+	}
+	progress.done();
 
 	ret = libusb_claim_interface(dev_handle, 0);
 	if (ret) {
@@ -72,6 +81,18 @@ FX2_ll::FX2_ll(uint16_t uninit_vid, uint16_t uninit_pid,
 	}
 }
 
+bool FX2_ll::set_interface_alt_setting(const int if_num, const int alt_setting)
+{
+	const int ret = libusb_set_interface_alt_setting(dev_handle, if_num,
+		alt_setting);
+	if (ret && ret != LIBUSB_ERROR_NOT_FOUND) {
+		printWarn("unable to select alternate interface 1: "
+			+ std::string(libusb_error_name(ret)));
+		return false;
+	}
+	return true;
+}
+
 /* destructor: close current device and
  * destroy context
  */
@@ -134,11 +155,11 @@ int FX2_ll::read(uint8_t endpoint, uint8_t *buff, uint16_t len)
 /* write len data using control
  */
 int FX2_ll::write_ctrl(uint8_t bRequest, uint16_t wValue,
-		uint8_t *buff, uint16_t len)
+		uint8_t *buff, uint16_t len, uint16_t wIndex)
 {
 	int ret = libusb_control_transfer(dev_handle,
 			LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_OUT,
-			bRequest, wValue, 0x0000, buff, len, 100);
+			bRequest, wValue, wIndex, buff, len, 100);
 	if (ret < 0) {
 		printError("Unable to send control request: "
 				+ std::string(libusb_error_name(ret)));
@@ -150,11 +171,11 @@ int FX2_ll::write_ctrl(uint8_t bRequest, uint16_t wValue,
 /* read len data using control
  */
 int FX2_ll::read_ctrl(uint8_t bRequest, uint16_t wValue,
-		uint8_t *buff, uint16_t len)
+		uint8_t *buff, uint16_t len, uint16_t wIndex)
 {
 	int ret = libusb_control_transfer(dev_handle,
 			LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_ENDPOINT_IN,
-			bRequest, wValue, 0x0000, buff, len, 100);
+			bRequest, wValue, wIndex, buff, len, 100);
 	if (ret < 0) {
 		printError("Unable to read control request: "
 				+ std::string(libusb_error_name(ret)));
@@ -177,6 +198,7 @@ bool FX2_ll::load_firmware(std::string firmware_path)
 		return false;
 	/* load */
 	std::vector<IhexParser::data_line_t> data = ihex.getDataArray();
+	ProgressBar progress("Loading firmware", data.size(), 50, false);
 	for (size_t i = 0; i < data.size(); i++) {
 		IhexParser::data_line_t data_line = data[i];
 
@@ -186,14 +208,16 @@ bool FX2_ll::load_firmware(std::string firmware_path)
 		while (toSend > 0) {
 			uint16_t xfer_len = (toSend > 64) ? 64: toSend;
 			if (!write_ctrl(FX2_FIRM_LOAD, addr, tx_buff, xfer_len)) {
-				printError("load firmware failed\n");
+				progress.fail();
 				return false;
 			}
 			toSend -= xfer_len;
 			tx_buff += xfer_len;
 			addr += xfer_len;
 		}
+		progress.display(i);
 	}
+	progress.done();
 
 	/* unset reset */
 	if (!reset(0))
diff --git a/src/fx2_ll.hpp b/src/fx2_ll.hpp
index 37eb1af..8040530 100644
--- a/src/fx2_ll.hpp
+++ b/src/fx2_ll.hpp
@@ -1,6 +1,6 @@
 // SPDX-License-Identifier: Apache-2.0
 /*
- * Copyright (c) 2021 Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
+ * Copyright (c) 2021-2026 Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
  */
 
 #ifndef SRC_FX2_LL_HPP_
@@ -31,6 +31,14 @@ class FX2_ll {
 				uint16_t vid, uint16_t pid, const std::string &firmware_path);
 		~FX2_ll();
 
+		/*!
+		 * \brief libusb_set_interface_alt_setting wrapper
+		 * \param[in] if_num: Interface number
+		 * \param[in] alt_setting: alternate setting
+		 * \return true on success
+		 */
+		bool set_interface_alt_setting(const int if_num, const int alt_setting);
+
 		/*!
 		 * \brief bulk write
 		 * \param[in] endpoint: endpoint to use
@@ -53,20 +61,22 @@ class FX2_ll {
 		 * \param[in] wValue
 		 * \param[in] buff: buffer to write
 		 * \param[in] len: buffer length
+		 * \param[in] wIndex: the index field for the setup packet
 		 * \return false when transfer fails, true otherwise
 		 */
 		int write_ctrl(uint8_t bRequest, uint16_t wValue,
-				uint8_t *buff, uint16_t len);
+				uint8_t *buff, uint16_t len, uint16_t wIndex=0x0000);
 		/*!
 		 * \brief control write
 		 * \param[in] bRequest
 		 * \param[in] wValue
 		 * \param[in] buff: buffer to write
 		 * \param[in] len: buffer length
+		 * \param[in] wIndex: the index field for the setup packet
 		 * \return false when transfer fails, true otherwise
 		 */
 		int read_ctrl(uint8_t bRequest, uint16_t wValue,
-				uint8_t *buff, uint16_t len);
+				uint8_t *buff, uint16_t len, uint16_t wIndex=0x0000);
 
 	private:
 		/*!