diff --git a/Multiprotocol/Bayang_nrf24l01.ino b/Multiprotocol/Bayang_nrf24l01.ino
index 8e761bf..226a06c 100644
--- a/Multiprotocol/Bayang_nrf24l01.ino
+++ b/Multiprotocol/Bayang_nrf24l01.ino
@@ -285,7 +285,7 @@ uint16_t BAYANG_callback()
 	switch(phase)
 	{
 		case BAYANG_BIND:
-			if (bind_counter-- == 0)
+			if (--bind_counter == 0)
 			{
 				XN297_SetTXAddr(rx_tx_addr, BAYANG_ADDRESS_LENGTH);
 				#ifdef BAYANG_HUB_TELEMETRY
@@ -326,7 +326,6 @@ uint16_t BAYANG_callback()
 			while ((uint16_t)((uint16_t)micros()-(uint16_t)start) < 1000)			// Wait max 1ms
 				if((NRF24L01_ReadReg(NRF24L01_07_STATUS) & _BV(NRF24L01_07_TX_DS)))
 					break;
-			debugln("time: %d",(uint16_t)((uint16_t)micros()-(uint16_t)start));
 			NRF24L01_WriteReg(NRF24L01_00_CONFIG, 0x03);
 			phase++;	// READ
 			return BAYANG_PACKET_TELEM_PERIOD - BAYANG_CHECK_DELAY - BAYANG_READ_DELAY;
diff --git a/Multiprotocol/Multi.txt b/Multiprotocol/Multi.txt
index 5bb313d..176f24a 100644
--- a/Multiprotocol/Multi.txt
+++ b/Multiprotocol/Multi.txt
@@ -43,7 +43,7 @@
 43,Traxxas,RX6519
 44,NCC1701
 45,E01X,E012,E015,E016H
-46,V911S
+46,V911S,Std
 47,GD00X,GD_V1,GD_V2
 48,V761
 49,KF606
@@ -59,4 +59,5 @@
 59,Bayang_RX
 60,Pelikan
 61,Tiger
+62,XK,X450,X420
 63,XN_DUMP,250K,1M,2M,AUTO
diff --git a/Multiprotocol/Multi_Names.ino b/Multiprotocol/Multi_Names.ino
index eb4eda8..120d4be 100644
--- a/Multiprotocol/Multi_Names.ino
+++ b/Multiprotocol/Multi_Names.ino
@@ -75,6 +75,7 @@ const char STR_FX816[]		="FX816";
 const char STR_BAYANG_RX[]	="BayanRX";
 const char STR_PELIKAN[]	="Pelikan";
 const char STR_TIGER[]		="Tiger";
+const char STR_XK[]			="XK";
 const char STR_XN297DUMP[]	="XN297DP";
 
 const char STR_SUBTYPE_FLYSKY[] =     "\x04""Std\0""V9x9""V6x6""V912""CX20";
@@ -115,6 +116,7 @@ const char STR_SUBTYPE_FX816[] =      "\x03""P38";
 const char STR_SUBTYPE_XN297DUMP[] =  "\x07""250Kbps""1Mbps\0 ""2Mbps\0 ""Auto\0  ";
 const char STR_SUBTYPE_ESKY150[] =    "\x03""4CH""7CH";
 const char STR_SUBTYPE_V911S[] =      "\x04""Std\0""E119";
+const char STR_SUBTYPE_XK[] =         "\x04""X450""X420";
 
 enum
 {
@@ -313,6 +315,9 @@ const mm_protocol_definition multi_protocols[] = {
 #if defined(TIGER_NRF24L01_INO)
 	{PROTO_TIGER,      STR_TIGER    , 0, NO_SUBTYPE,            OPTION_NONE    },	
 #endif
+#if defined(XK_NRF24L01_INO)
+	{PROTO_XK,         STR_XK       , 2, STR_SUBTYPE_XK,        OPTION_RFTUNE  },	
+#endif
 #if defined(XN297DUMP_NRF24L01_INO)
 	{PROTO_XN297DUMP,  STR_XN297DUMP, 4, STR_SUBTYPE_XN297DUMP, OPTION_RFCHAN  },
 #endif
diff --git a/Multiprotocol/Multiprotocol.h b/Multiprotocol/Multiprotocol.h
index 73de653..46b4044 100644
--- a/Multiprotocol/Multiprotocol.h
+++ b/Multiprotocol/Multiprotocol.h
@@ -19,7 +19,7 @@
 #define VERSION_MAJOR		1
 #define VERSION_MINOR		3
 #define VERSION_REVISION	0
-#define VERSION_PATCH_LEVEL	56
+#define VERSION_PATCH_LEVEL	57
 
 //******************
 // Protocols
@@ -88,6 +88,7 @@ enum PROTOCOLS
 	PROTO_BAYANG_RX	= 59,	// =>NRF24L01
 	PROTO_PELIKAN	= 60,	// =>A7105
 	PROTO_TIGER		= 61,	// =>NRF24L01
+	PROTO_XK		= 62,	// =>NRF24L01
 	PROTO_XN297DUMP	= 63,	// =>NRF24L01
 };
 
@@ -305,6 +306,11 @@ enum V911S
 	V911S_STD	= 0,
 	V911S_E119	= 1,
 };
+enum XK
+{
+	X450	= 0,
+	X420	= 1,
+};
 enum XN297DUMP
 {
 	XN297DUMP_250K	= 0,
@@ -703,6 +709,8 @@ Serial: 100000 Baud 8e2      _ xxxx xxxx p --
 				BAYANG_RX	59
 				PELIKAN		60
 				TIGER		61
+				XK			62
+				XN297DUMP	63
    BindBit=>		0x80	1=Bind/0=No
    AutoBindBit=>	0x40	1=Yes /0=No
    RangeCheck=>		0x20	1=Yes /0=No
@@ -850,6 +858,12 @@ Serial: 100000 Baud 8e2      _ xxxx xxxx p --
 		sub_protocol==V911S
 			V911S_STD	0
 			V911S_E119	1
+		sub_protocol==XK
+			X450		0
+			X420		1
+		sub_protocol==V911S
+			V911S_STD	0
+			V911S_E119	1
 
    Power value => 0x80	0=High/1=Low
   Stream[3]   = option_protocol;
diff --git a/Multiprotocol/Multiprotocol.ino b/Multiprotocol/Multiprotocol.ino
index 1a5b461..771c8df 100644
--- a/Multiprotocol/Multiprotocol.ino
+++ b/Multiprotocol/Multiprotocol.ino
@@ -1478,6 +1478,12 @@ static void protocol_init()
 						remote_callback = TIGER_callback;
 						break;
 				#endif
+				#if defined(XK_NRF24L01_INO)
+					case PROTO_XK:
+						next_callback=initXK();
+						remote_callback = XK_callback;
+						break;
+				#endif
 				#if defined(XN297DUMP_NRF24L01_INO)
 					case PROTO_XN297DUMP:
 						next_callback=initXN297Dump();
diff --git a/Multiprotocol/Validate.h b/Multiprotocol/Validate.h
index 50906f1..8159fef 100644
--- a/Multiprotocol/Validate.h
+++ b/Multiprotocol/Validate.h
@@ -248,6 +248,7 @@
 	#undef	ZSX_NRF24L01_INO
 	#undef	BAYANG_RX_NRF24L01_INO
 	#undef	TIGER_NRF24L01_INO
+	#undef	XK_NRF24L01_INO
 #endif
 
 //Make sure telemetry is selected correctly
diff --git a/Multiprotocol/XK_nrf24l01.ino b/Multiprotocol/XK_nrf24l01.ino
new file mode 100644
index 0000000..ad808de
--- /dev/null
+++ b/Multiprotocol/XK_nrf24l01.ino
@@ -0,0 +1,179 @@
+/*
+ This project is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+Multiprotocol is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with Multiprotocol.  If not, see <http://www.gnu.org/licenses/>.
+ */
+// Compatible with X450 and X420 plane.
+
+#if defined(XK_NRF24L01_INO)
+
+#include "iface_xn297l.h"
+
+#define FORCE_XK_ORIGINAL_ID
+
+#define XK_INITIAL_WAIT		500
+#define XK_PACKET_PERIOD		4000
+#define XK_RF_BIND_NUM_CHANNELS 8
+#define XK_RF_NUM_CHANNELS	4
+#define XK_PAYLOAD_SIZE		16
+#define XK_BIND_COUNT			750	//3sec
+
+static uint16_t __attribute__((unused)) XK_convert_channel(uint8_t num)
+{
+	uint16_t val=convert_channel_10b(num);
+	// 1FF..01=left, 00=center, 200..3FF=right
+	if(val==0x200)
+		val=0;				// 0
+	else
+		if(val>0x200)
+			val--;			// 200..3FE
+		else
+		{
+			val=0x200-val;	// 200..01
+			if(val==0x200)
+				val--;		// 1FF..01
+		}
+	return val;
+}
+
+static void __attribute__((unused)) XK_send_packet()
+{
+	memset(packet,0x00,16);
+	
+	memcpy(&packet[7],rx_tx_addr,3);
+	packet[12]=0x40;
+	packet[13]=0x40;
+	if(IS_BIND_IN_PROGRESS)
+		packet[14] = 0xC0;
+	else
+	{
+		uint16_t val=convert_channel_10b(THROTTLE);
+		packet[0] = val>>2;						// 0..255
+		packet[12] |= val & 2;
+		val=XK_convert_channel(RUDDER);
+		packet[1] = val>>2;
+		packet[12] |= (val & 2)<<2;
+		val=XK_convert_channel(ELEVATOR);
+		packet[2] = val>>2;
+		packet[13] |= val & 2;
+		val=XK_convert_channel(AILERON);
+		packet[3] = val>>2;
+		packet[13] |= (val & 2)<<2;
+		
+		memset(&packet[4],0x40,3);				// Trims
+		
+		if(Channel_data[CH5] > CHANNEL_MAX_COMMAND)
+			packet[10] = 0x10; 					// V-Mode
+		else
+			if(Channel_data[CH5] > CHANNEL_MIN_COMMAND)
+				packet[10] = 0x04; 				// 6G-Mode
+		//0x00 default M-Mode
+		packet[10] |= GET_FLAG(CH7_SW,0x80);	// Emergency stop momentary switch
+
+		packet[11]  = GET_FLAG(CH8_SW,0x03)		// 3D/6G momentary switch
+					 |GET_FLAG(CH6_SW,0x40);	// Take off momentary switch
+		packet[14]  = GET_FLAG(CH9_SW,0x01);	// Photo momentary switch
+	}
+
+	crc=packet[0];
+	for(uint8_t i=1; i<XK_PAYLOAD_SIZE-1;i++)
+		crc+=packet[i];
+	packet[15]=crc;
+
+	//debug("C: %02X, P:",hopping_frequency[(IS_BIND_IN_PROGRESS?0:XK_RF_BIND_NUM_CHANNELS)+(hopping_frequency_no>>1)]);
+	XN297L_Hopping((IS_BIND_IN_PROGRESS?0:XK_RF_BIND_NUM_CHANNELS)+(hopping_frequency_no>>1));
+	hopping_frequency_no++;
+	if(hopping_frequency_no >= (IS_BIND_IN_PROGRESS?XK_RF_BIND_NUM_CHANNELS*2:XK_RF_NUM_CHANNELS*2))
+		hopping_frequency_no=0;
+
+	XN297L_WritePayload(packet, XK_PAYLOAD_SIZE);
+	//for(uint8_t i=0; i<XK_PAYLOAD_SIZE; i++)
+	//	debug(" %02X",packet[i]);
+	//debugln("");
+	
+	XN297L_SetPower();		// Set tx_power
+	XN297L_SetFreqOffset();	// Set frequency offset
+}
+
+const uint8_t PROGMEM XK_bind_hop[XK_RF_BIND_NUM_CHANNELS]= { 0x07, 0x24, 0x3E, 0x2B, 0x47, 0x0E, 0x39, 0x1C };	// Bind
+
+static void __attribute__((unused)) XK_initialize_txid()
+{
+	//bind hop
+	for(uint8_t i=0; i<XK_RF_BIND_NUM_CHANNELS; i++)
+		hopping_frequency[i]=pgm_read_byte_near( &XK_bind_hop[i] );
+
+	//#ifdef FORCE_XK_ORIGINAL_ID
+		if(sub_protocol==X450)
+		{
+			//TX1 X8 X450
+			rx_tx_addr[0]=0x04;
+			rx_tx_addr[1]=0x15;
+			rx_tx_addr[2]=0x22;
+			memcpy(&hopping_frequency[XK_RF_BIND_NUM_CHANNELS],"\x3B\x48\x40\x49", XK_RF_NUM_CHANNELS);	// freq and order verified
+			//Normal packet address \x2C\x96\x2A\xA9\x32
+
+			//TX2 X450 X8?
+			//rx_tx_addr[0]=0x24;
+			//rx_tx_addr[1]=0x14;
+			//rx_tx_addr[2]=0x22;
+			//memcpy(&hopping_frequency[XK_RF_BIND_NUM_CHANNELS],"\x3A\x3B\x42\x48", XK_RF_NUM_CHANNELS);	// freq unsure and order unknown
+			//Normal packet address \x2C\x96\x2A\xA9\x32
+		}
+		else
+		{
+			//TX3 X420
+			rx_tx_addr[0]=0x13;
+			rx_tx_addr[1]=0x24;
+			rx_tx_addr[2]=0x18;
+			memcpy(&hopping_frequency[XK_RF_BIND_NUM_CHANNELS],"\x36\x37\x41\x4E", XK_RF_NUM_CHANNELS);	// freq ok but order unknown
+			//Normal packet address \xA6\x83\xEB\x4B\xC9
+		}
+	//#endif
+}
+
+static void __attribute__((unused)) XK_init()
+{
+	XN297L_Init();
+	XN297L_SetTXAddr((uint8_t*)"\x68\x94\xA6\xD5\xC3", 5);					// Bind address
+	XN297L_HoppingCalib(XK_RF_BIND_NUM_CHANNELS+XK_RF_NUM_CHANNELS);	// Calibrate all channels
+}
+
+uint16_t XK_callback()
+{
+	#ifdef MULTI_SYNC
+		telemetry_set_input_sync(XK_PACKET_PERIOD);
+	#endif
+	if(IS_BIND_IN_PROGRESS)
+		if(--bind_counter==0)
+		{
+			BIND_DONE;
+			if(sub_protocol==X450)
+				XN297L_SetTXAddr((uint8_t*)"\x2C\x96\x2A\xA9\x32", 5);			// Normal address X450
+			else
+				XN297L_SetTXAddr((uint8_t*)"\xA6\x83\xEB\x4B\xC9", 5);			// Normal address X420
+		}
+	XK_send_packet();
+	return XK_PACKET_PERIOD;
+}
+
+uint16_t initXK()
+{
+	BIND_IN_PROGRESS;	// autobind protocol
+	XK_initialize_txid();
+	XK_init();
+	hopping_frequency_no = 0;
+	bind_counter=XK_BIND_COUNT;
+	return XK_INITIAL_WAIT;
+}
+
+#endif
diff --git a/Multiprotocol/_Config.h b/Multiprotocol/_Config.h
index 746f47a..2cec993 100644
--- a/Multiprotocol/_Config.h
+++ b/Multiprotocol/_Config.h
@@ -218,6 +218,7 @@
 #define	V2X2_NRF24L01_INO
 #define	V761_NRF24L01_INO
 #define	V911S_NRF24L01_INO
+#define	XK_NRF24L01_INO
 #define	YD717_NRF24L01_INO
 #define	ZSX_NRF24L01_INO
 
@@ -676,6 +677,9 @@ const PPM_Parameters PPM_prot[14*NBR_BANKS]=	{
 		W6_6_1
 		W6_HEL
 		W6_HEL_I
+	PROTO_XK
+		X450
+		X420
 	PROTO_YD717
 		YD717
 		SKYWLKR