diff --git a/src_main/io/pibasetransfer.cpp b/src_main/io/pibasetransfer.cpp
index 9cd1cc84..745353f0 100644
--- a/src_main/io/pibasetransfer.cpp
+++ b/src_main/io/pibasetransfer.cpp
@@ -5,6 +5,7 @@ const uint PIBaseTransfer::signature = 0x54424950;
 
 PIBaseTransfer::PIBaseTransfer(): crc(standardCRC_16()), diag(false) {
 	header.sig = signature;
+	crc_enabled = true;
 	header.session_id = 0;
 	packet_header_size = sizeof(PacketHeader) + customHeader().size();
 	part_header_size = sizeof(Part) + sizeof(int);
@@ -77,7 +78,9 @@ void PIBaseTransfer::received(PIByteArray data) {
 				return;
 			} else {
 				uint rcrc = h.crc;
-				uint ccrc = crc.calculate(data.data(), data.size_s());
+				uint ccrc;
+				if (crc_enabled) ccrc = crc.calculate(data.data(), data.size_s());
+				else ccrc = 0;
 				if (rcrc != ccrc) {
 					header.id = h.id;
 					piCoutObj << "invalid CRC";
@@ -523,7 +526,8 @@ PIByteArray PIBaseTransfer::build_packet(int id) {
 	mutex_header.lock();
 	header.id = id + 1;
 	header.type = pt_Data;
-	header.crc = crc.calculate(ret);
+	if (crc_enabled) header.crc = crc.calculate(ret);
+	else header.crc = 0;
 	hdr << header;
 	mutex_header.unlock();
 	ret.insert(0, hdr);
diff --git a/src_main/io/pibasetransfer.h b/src_main/io/pibasetransfer.h
index f5001e63..52fac139 100644
--- a/src_main/io/pibasetransfer.h
+++ b/src_main/io/pibasetransfer.h
@@ -65,6 +65,9 @@ public:
 	void setTimeout(double sec) {timeout_ = sec; diag.setDisconnectTimeout(sec);}
 	double timeout() const {return timeout_;}
 
+	void setCRCEnabled(bool en = true) {crc_enabled = en;}
+	bool isCRCEnabled() const {return crc_enabled;}
+
 	const PIString & stateString() const {return state_string;}
 	llong bytesAll() const {return bytes_all;}
 	llong bytesCur() const {return bytes_cur;}
@@ -89,19 +92,18 @@ public:
 	EVENT1(sendRequest, PIByteArray &, data)
 
 protected:
+	void buildSession(PIVector<Part> parts);
+	virtual PIByteArray buildPacket(Part fi) = 0;
+	virtual void receivePart(Part fi, PIByteArray ba, PIByteArray pheader) = 0;
+	virtual PIByteArray customHeader() {return PIByteArray();}
+	bool send_process();
+	
 	uint packet_header_size, part_header_size;
 	bool break_, is_sending, is_receiving, is_pause;
 	PIString state_string;
 	llong bytes_all, bytes_cur;
-	
-	void buildSession(PIVector<Part> parts);
-	virtual PIByteArray buildPacket(Part fi) = 0;
-    virtual void receivePart(Part fi, PIByteArray ba, PIByteArray pheader) = 0;
-	virtual PIByteArray customHeader() {return PIByteArray();}
-	bool send_process();
-	
-private:
 
+private:
 	enum PacketType {pt_Unknown, pt_Data, pt_ReplySuccess, pt_ReplyInvalid, pt_Break, pt_Start, pt_Pause};
 
 # pragma pack(push,1)
@@ -114,6 +116,15 @@ private:
 	friend PIByteArray & operator >>(PIByteArray & s, PIBaseTransfer::StartRequest & v);
 	friend PIByteArray & operator <<(PIByteArray & s, const PIBaseTransfer::StartRequest & v);
 
+	void processData(int id, PIByteArray &data);
+	PIByteArray build_packet(int id);
+	int checkSession();
+	void sendBreak(int session_id);
+	void sendReply(PacketType reply);
+	bool getStartRequest();
+	bool finish_send(bool ok);
+	void finish_receive(bool ok, bool quet = false);
+
 	static const uint signature;
 	int packet_size, packets_count;
 	double timeout_;
@@ -127,15 +138,7 @@ private:
 	PIMutex mutex_session;
 	PIMutex mutex_send;
 	PIMutex mutex_header;
-
-	void processData(int id, PIByteArray &data);
-	PIByteArray build_packet(int id);
-	int checkSession();
-	void sendBreak(int session_id);
-	void sendReply(PacketType reply);
-	bool getStartRequest();
-	bool finish_send(bool ok);
-	void finish_receive(bool ok, bool quet = false);
+	bool crc_enabled;
 };
 
 inline PIByteArray & operator <<(PIByteArray & s, const PIBaseTransfer::PacketHeader & v) {s << v.sig << v.type << v.session_id << v.id << v.crc; return s;}
diff --git a/src_main/io/pipeer.cpp b/src_main/io/pipeer.cpp
index a1fee1b5..232268b3 100755
--- a/src_main/io/pipeer.cpp
+++ b/src_main/io/pipeer.cpp
@@ -37,6 +37,8 @@
 PIPeer::PeerData::PeerData(const PIString & n): PIObject(n) {
 	dt_in.setPacketSize(_PIPEER_MSG_SIZE);
 	dt_out.setPacketSize(_PIPEER_MSG_SIZE);
+	dt_in.setCRCEnabled(false);
+	dt_out.setCRCEnabled(false);
 	CONNECTU(&dt_in, sendRequest, this, dtSendRequestIn)
 	CONNECTU(&dt_out, sendRequest, this, dtSendRequestOut)
 	CONNECTU(&dt_in, receiveFinished, this, dtReceiveFinishedIn)
diff --git a/utils/system_daemon/daemon.cpp b/utils/system_daemon/daemon.cpp
index 7364709b..9379a23c 100644
--- a/utils/system_daemon/daemon.cpp
+++ b/utils/system_daemon/daemon.cpp
@@ -12,6 +12,7 @@ Daemon::Remote::Remote(const PIString & n): PIThread() {
 	term = 0;
 	ft.setName(n);
 	ft.setPacketSize(3984);
+	ft.setCRCEnabled(false);
 	CONNECTU(&ft, sendRequest, this, ftSendRequest)
 	CONNECTU(&ft, receiveFilesFinished, this, ftReceived)
 	CONNECTU(&ft, sendFilesFinished, this, ftSended)
@@ -269,6 +270,7 @@ Daemon::Daemon(): PIPeer(pisd_prefix + PISystemInfo::instance()->hostname + "_"
 	CONNECTU(_self, sendFinished, this, closeFileDialog)
 	CONNECTU(_self, changeDirFinished, this, dirChanged)
 	localft.setName(self_name);
+	localft.setCRCEnabled(false);
 	CONNECTU(&localft, sendRequest, _self, received)
 	dtimer.addDelimiter(5);
 	dtimer.start(200);
diff --git a/utils/udp_file_transfer/main.cpp b/utils/udp_file_transfer/main.cpp
index e1d5fa48..54bda7ca 100644
--- a/utils/udp_file_transfer/main.cpp
+++ b/utils/udp_file_transfer/main.cpp
@@ -14,7 +14,8 @@ public:
 		eth.setReadAddress(src_ip_port);
 		eth.setSendAddress(dst_ip_port);
 		if (test_) {
-			testt.setPacketSize(1280);
+			testt.setCRCEnabled(false);
+			//testt.setPacketSize(1280);
 			testt.setName("TEST");
 			//testt.setTimeout(0.1);
 			CONNECTU(&testt, sendRequest, this, ftsend);
@@ -40,7 +41,7 @@ public:
 	}
 
 	void startTest() {
-		PIByteArray ba(1024*1024*64);
+		PIByteArray ba(1024*1024*256);
 		testt.send(ba);
 	}