diff --git a/src/altera.cpp b/src/altera.cpp
index fdef8c3..a773531 100644
--- a/src/altera.cpp
+++ b/src/altera.cpp
@@ -31,7 +31,7 @@ Altera::Altera(Jtag *jtag, const std::string &filename,
 	Device(jtag, filename, file_type, verify, verbose),
 	SPIInterface(filename, verbose, 256, verify, skip_load_bridge,
 				 skip_reset),
-	_svf(_jtag, _verbose), _device_package(device_package),
+	_device_package(device_package),
 	_vir_addr(0x1000), _vir_length(14)
 {
 	if (prg_type == Device::RD_FLASH) {
@@ -216,13 +216,9 @@ void Altera::program(unsigned int offset, bool unprotect_flash)
 	 */
 	/* mem mode -> svf */
 	if (_mode == Device::MEM_MODE) {
-		if (_file_extension == "svf") {
-			_svf.parse(_filename);
-		} else {
-			RawParser _bit(_filename, false);
-			_bit.parse();
-			programMem(_bit);
-		}
+		RawParser _bit(_filename, false);
+		_bit.parse();
+		programMem(_bit);
 	} else if (_mode == Device::SPI_MODE) {
 		// reverse only bitstream raw binaries data no
 		bool reverseOrder = false;
diff --git a/src/altera.hpp b/src/altera.hpp
index 12af383..c336eef 100644
--- a/src/altera.hpp
+++ b/src/altera.hpp
@@ -99,7 +99,6 @@ class Altera: public Device, SPIInterface {
 		void shiftVDR(uint8_t * tx, uint8_t * rx, uint32_t len,
 				int end_state = Jtag::UPDATE_DR, bool debug = false);
 
-		SVF_jtag _svf;
 		std::string _device_package;
 		uint32_t _vir_addr; /**< addr affected to virtual jtag */
 		uint32_t _vir_length; /**< length of virtual jtag IR */
diff --git a/src/anlogic.cpp b/src/anlogic.cpp
index d42d050..9c0b966 100644
--- a/src/anlogic.cpp
+++ b/src/anlogic.cpp
@@ -29,7 +29,7 @@ Anlogic::Anlogic(Jtag *jtag, const std::string &filename,
 	const std::string &file_type,
 	Device::prog_type_t prg_type, bool verify, int8_t verbose):
 	Device(jtag, filename, file_type, verify, verbose),
-	SPIInterface(filename, verbose, 0, verify), _svf(_jtag, _verbose)
+	SPIInterface(filename, verbose, 0, verify)
 {
 	if (prg_type == Device::RD_FLASH) {
 		_mode = Device::READ_MODE;
@@ -64,11 +64,6 @@ void Anlogic::program(unsigned int offset, bool unprotect_flash)
 	if (_mode == Device::NONE_MODE)
 		return;
 
-	if (_file_extension == "svf") {
-		_svf.parse(_filename);
-		return;
-	}
-
 	AnlogicBitParser bit(_filename, (_mode == Device::MEM_MODE), _verbose);
 
 	printInfo("Parse file ", false);
diff --git a/src/anlogic.hpp b/src/anlogic.hpp
index 970a3b4..20fd23b 100644
--- a/src/anlogic.hpp
+++ b/src/anlogic.hpp
@@ -73,8 +73,6 @@ class Anlogic: public Device, SPIInterface {
 		 */
 		virtual bool post_flash_access() override {reset(); return true;}
 
-	private:
-		SVF_jtag _svf;
 };
 
 #endif  // SRC_ANLOGIC_HPP_
diff --git a/src/main.cpp b/src/main.cpp
index db04aa6..03efc8d 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -31,6 +31,7 @@
 #include "spiFlash.hpp"
 #include "rawParser.hpp"
 #include "xilinx.hpp"
+#include "svf_jtag.hpp"
 #ifdef ENABLE_XVC
 #include "xvc_server.hpp"
 #endif
@@ -496,7 +497,20 @@ int main(int argc, char **argv)
 
 	jtag->device_select(index);
 
-	/* check if selected device is supported
+	/* detect svf file and program the device */
+	if (!args.bit_file.empty() && 
+		((!args.file_type.empty() && args.file_type == "svf") ||
+		 (args.bit_file.substr(args.bit_file.find_last_of(".") + 1) == "svf"))) {
+		SVF_jtag *svf = new SVF_jtag(jtag, args.verbose);
+		try {
+			svf->parse(args.bit_file);
+		} catch (std::exception &e) {
+			return EXIT_FAILURE;
+		}
+		return EXIT_SUCCESS;
+	}
+
+    /* check if selected device is supported
 	 * mainly used in conjunction with --index-chain
 	 */
 	if (fpga_list.find(idcode) == fpga_list.end()) {
diff --git a/src/svf_jtag.cpp b/src/svf_jtag.cpp
index 75a7b52..bd1800f 100644
--- a/src/svf_jtag.cpp
+++ b/src/svf_jtag.cpp
@@ -42,8 +42,8 @@ static unsigned char *parse_hex(string const &in, size_t byte_length,
 {
 	unsigned char *txbuf = new unsigned char[byte_length];
 	char c;
-	size_t last_iter = in.size() - (2 * byte_length);
-	for (size_t i = (in.size() - 1), pos = 0; i >= last_iter; i--, pos++) {
+	ssize_t last_iter = in.size() - (2 * byte_length);
+	for (ssize_t i = (in.size() - 1), pos = 0; i >= last_iter; i--, pos++) {
 		if (i < 0) {
 			c = default_value ? 0x0f : 0x00;
 		} else {