diff --git a/src/configBitstreamParser.cpp b/src/configBitstreamParser.cpp
index a96bf59..67acba8 100644
--- a/src/configBitstreamParser.cpp
+++ b/src/configBitstreamParser.cpp
@@ -21,6 +21,7 @@ ConfigBitstreamParser::ConfigBitstreamParser(const string &filename, int mode,
 			_file_size(0), _verbose(verbose),
 			_bit_data(), _raw_data(), _hdr()
 {
+	(void) mode;
 	if (!filename.empty()) {
 		FILE *_fd = fopen(filename.c_str(), "rb");
 		if (!_fd)
diff --git a/src/fsparser.cpp b/src/fsparser.cpp
index c333e5f..b9e294a 100644
--- a/src/fsparser.cpp
+++ b/src/fsparser.cpp
@@ -185,7 +185,7 @@ int FsParser::parse()
 	/* For configuration data checksum: number of lines can't be higher than
 	 * the number indicates in TN653 but may be smaller (seen with the GW1NS-2C).
 	 */
-	if (stoi(_hdr["ConfDataLength"]) < nb_line)
+	if (stoul(_hdr["ConfDataLength"]) < nb_line)
 		nb_line = stoi(_hdr["ConfDataLength"]);
 
 	/* drop now useless header */
diff --git a/src/fx2_ll.cpp b/src/fx2_ll.cpp
index 8641ba5..9f3164f 100644
--- a/src/fx2_ll.cpp
+++ b/src/fx2_ll.cpp
@@ -32,7 +32,7 @@ FX2_ll::FX2_ll(uint16_t uninit_vid, uint16_t uninit_pid,
 	}
 
 	/* try to open uninitialized device */
-	if (uninit_vid != -1 && uninit_pid != -1) {
+	if (uninit_vid != 0 && uninit_pid != 0) {
 		dev_handle = libusb_open_device_with_vid_pid(usb_ctx,
 				uninit_vid, uninit_pid);
 		if (dev_handle) {
diff --git a/src/usbBlaster.cpp b/src/usbBlaster.cpp
index 1e9f4a8..c80a794 100644
--- a/src/usbBlaster.cpp
+++ b/src/usbBlaster.cpp
@@ -42,6 +42,7 @@ UsbBlaster::UsbBlaster(int vid, int pid, const std::string &firmware_path,
 			_verbose(verbose), _nb_bit(0),
 			_curr_tms(0), _buffer_size(64)
 {
+	(void) vid;
 	if (pid == 0x6001)
 		ll_driver = new UsbBlasterI();
 	else if (pid == 0x6810)