diff --git a/firmware/common/Makefile_inc.mk b/firmware/common/Makefile_inc.mk
index 4b51f8fa..8917beda 100644
--- a/firmware/common/Makefile_inc.mk
+++ b/firmware/common/Makefile_inc.mk
@@ -50,7 +50,7 @@ OBJDUMP = $(PREFIX)-objdump
 GDB = $(PREFIX)-gdb
 TOOLCHAIN_DIR := $(shell dirname `which $(CC)`)/../$(PREFIX)
 
-CFLAGS += -std=c99 -Os -g3 -Wall -Wextra -I$(LIBOPENCM3)/include -I../common \
+CFLAGS += -std=gnu99 -Os -g3 -Wall -Wextra -I$(LIBOPENCM3)/include -I../common \
 		-fno-common -mcpu=cortex-m4 -mthumb -MD \
 		-mfloat-abi=hard -mfpu=fpv4-sp-d16 \
 		$(HACKRF_OPTS)
diff --git a/firmware/common/hackrf_core.c b/firmware/common/hackrf_core.c
index 062d7fe9..d1be02e7 100644
--- a/firmware/common/hackrf_core.c
+++ b/firmware/common/hackrf_core.c
@@ -39,6 +39,69 @@ void delay(uint32_t duration)
 		__asm__("nop");
 }
 
+bool set_fracrate(const float freq) {
+
+	uint32_t MSx_P1,MSx_P2,MSx_P3;
+	uint32_t b,c;
+	float div = (800/freq);
+	uint32_t a = (uint32_t)div;
+	float x = div-a;
+
+	if(a != div){
+		uint32_t j=0,k=1,l=1,m=1;
+		while (k <= 0xFFFF && m <= 0xFFFF){
+			float n = (float)(j+l)/(k+m);
+			if( x == n){
+				if(k + m <= 0xFFFF){
+					b=j+l;	c=k+m;
+					break;
+				} else if(m > k){
+					b=l; c=m;
+					break;
+				} else {
+					b=j; c=k;
+					break;
+				}
+			}
+			else if(x > n){
+				j+=l; k+=m;
+			}
+			else{
+				l+=j; m+=k;
+			}
+		}
+		if (k > 0xFFFF){
+			b=l; c=m;
+		}
+		else{
+			b=j; c=k;
+		}
+	} else {
+		b=0; c=1;
+	}
+
+	MSx_P1 = 128*a + (128 * b/c) - 512;
+	MSx_P2 = (128*b)%c;
+	MSx_P3 = c;
+
+	
+	/* MS0/CLK0 is the source for the MAX5864/CPLD (CODEC_CLK). */
+	si5351c_configure_multisynth(0, MSx_P1, MSx_P2, MSx_P3, 1);
+
+	/* MS0/CLK1 is the source for the CPLD (CODEC_X2_CLK). */
+	si5351c_configure_multisynth(1, 0, 0, 0, 0);//p1 doesn't matter
+
+	/* MS0/CLK2 is the source for SGPIO (CODEC_X2_CLK) */
+	si5351c_configure_multisynth(2, 0, 0, 0, 0);//p1 doesn't matter
+
+	/* MS0/CLK3 is the source for the external clock output. */
+	//si5351c_configure_multisynth(3, p1, 0, 1, 0); // no clk out
+
+	return true;
+
+}
+
+
 bool sample_rate_set(const uint32_t sample_rate_hz) {
 #ifdef JELLYBEAN
 	/* Due to design issues, Jellybean/Lemondrop frequency plan is limited.
@@ -88,26 +151,26 @@ bool sample_rate_set(const uint32_t sample_rate_hz) {
 #ifdef JAWBREAKER
 	uint32_t p1 = 4608;
 	
-	switch(sample_rate_hz) {
-	case 5000000:
-		p1 = 9728;	// 800MHz / 80 = 10 MHz (SGPIO), 5 MHz (codec)
-		break;
-	
-	case 10000000:
-		p1 = 4608;	// 800MHz / 40 = 20 MHz (SGPIO), 10 MHz (codec)
-		break;
-
-	case 12500000:
-		p1 = 3584;	// 800MHz / 32 = 25 MHz (SGPIO), 12.5 MHz (codec)
-		break;
-
-	case 16000000:
-		p1 = 2688;	// 800MHz / 25 = 32 MHz (SGPIO), 16 MHz (codec)
-		break;
-	
-	case 20000000:
-		p1 = 2048;	// 800MHz / 20 = 40 MHz (SGPIO), 20 MHz (codec)
+ 	switch(sample_rate_hz) {
+	case 8000000:
+		p1 = SI_INTDIV(50);	// 800MHz / 50 = 16 MHz (SGPIO), 8 MHz (codec)
 		break;
+		
+ 	case 10000000:
+		p1 = SI_INTDIV(40);	// 800MHz / 40 = 20 MHz (SGPIO), 10 MHz (codec)
+ 		break;
+ 
+ 	case 12500000:
+		p1 = SI_INTDIV(32);	// 800MHz / 32 = 25 MHz (SGPIO), 12.5 MHz (codec)
+ 		break;
+ 
+ 	case 16000000:
+		p1 = SI_INTDIV(25);	// 800MHz / 25 = 32 MHz (SGPIO), 16 MHz (codec)
+ 		break;
+ 	
+ 	case 20000000:
+		p1 = SI_INTDIV(20);	// 800MHz / 20 = 40 MHz (SGPIO), 20 MHz (codec)
+ 		break;
 	
 	default:
 		return false;
@@ -117,13 +180,13 @@ bool sample_rate_set(const uint32_t sample_rate_hz) {
 	si5351c_configure_multisynth(0, p1, 0, 1, 1);
 
 	/* MS0/CLK1 is the source for the CPLD (CODEC_X2_CLK). */
-	si5351c_configure_multisynth(1, p1, 0, 1, 0);
+	si5351c_configure_multisynth(1, p1, 0, 1, 0);//p1 doesn't matter
 
 	/* MS0/CLK2 is the source for SGPIO (CODEC_X2_CLK) */
-	si5351c_configure_multisynth(2, p1, 0, 1, 0);
+	si5351c_configure_multisynth(2, p1, 0, 1, 0);//p1 doesn't matter
 
 	/* MS0/CLK3 is the source for the external clock output. */
-	si5351c_configure_multisynth(3, p1, 0, 1, 0);
+	//si5351c_configure_multisynth(3, p1, 0, 1, 0); // no clk out
 
 	return true;
 #endif
@@ -186,19 +249,23 @@ void cpu_clock_init(void)
 	 */
 
 	/* MS4/CLK4 is the source for the RFFC5071 mixer. */
-	si5351c_configure_multisynth(4, 1536, 0, 1, 0); /* 50MHz */
-
-	/* MS5/CLK5 is the source for the MAX2837 clock input. */
-	si5351c_configure_multisynth(5, 2048, 0, 1, 0); /* 40MHz */
+	si5351c_configure_multisynth(4, 16*128-512, 0, 1, 0); /* 800/16 = 50MHz */
+ 
+ 	/* MS5/CLK5 is the source for the MAX2837 clock input. */
+	si5351c_configure_multisynth(5, 20*128-512, 0, 1, 0); /* 800/20 = 40MHz */
 
 	/* MS7/CLK7 is the source for the LPC43xx microcontroller. */
-	//si5351c_configure_multisynth(7, 8021, 0, 3, 0); /* 12MHz */
+	//uint8_t ms7data[] = { 91, 40, 0x0 };
+	//si5351c_write(ms7data, sizeof(ms7data));
 #endif
 
 	/* Set to 10 MHz, the common rate between Jellybean and Jawbreaker. */
 	sample_rate_set(10000000);
 
 	si5351c_configure_clock_control();
+	// soft reset
+	uint8_t resetdata[] = { 177, 0xac };
+	si5351c_write(resetdata, sizeof(resetdata));
 	si5351c_enable_clock_outputs();
 
 	//FIXME disable I2C
@@ -405,6 +472,9 @@ void pin_setup(void) {
 	scu_pinmux(SCU_SSP1_MOSI, (SCU_SSP_IO | SCU_CONF_FUNCTION5));
 	scu_pinmux(SCU_SSP1_SCK, (SCU_SSP_IO | SCU_CONF_FUNCTION1));
 	scu_pinmux(SCU_SSP1_SSEL, (SCU_SSP_IO | SCU_CONF_FUNCTION1));
+	
+	/* Configure external clock in */
+	//scu_pinmux(P4_7, SCU_CLK_IN | SCU_CONF_FUNCTION1);
 }
 
 void enable_1v8_power(void) {
diff --git a/firmware/common/hackrf_core.h b/firmware/common/hackrf_core.h
index 462f8b1d..d32f27e4 100644
--- a/firmware/common/hackrf_core.h
+++ b/firmware/common/hackrf_core.h
@@ -259,6 +259,7 @@ void pin_setup(void);
 
 void enable_1v8_power(void);
 
+bool set_fracrate(const float sampling_rate_mhz);
 bool sample_rate_set(const uint32_t sampling_rate_hz);
 bool baseband_filter_bandwidth_set(const uint32_t bandwidth_hz);
 
diff --git a/firmware/common/si5351c.c b/firmware/common/si5351c.c
index eff4b498..6cc0d253 100644
--- a/firmware/common/si5351c.c
+++ b/firmware/common/si5351c.c
@@ -87,7 +87,16 @@ void si5351c_disable_oeb_pin_control()
 /* Power down all CLKx */
 void si5351c_power_down_all_clocks()
 {
-	uint8_t data[] = { 16, 0x80, 0x80, 0x80, 0x80, 0x80, 0x80, 0xC0, 0xC0 };
+	uint8_t data[] = { 16
+	, SI5351C_CLK_POWERDOWN
+	, SI5351C_CLK_POWERDOWN
+	, SI5351C_CLK_POWERDOWN
+	, SI5351C_CLK_POWERDOWN
+	, SI5351C_CLK_POWERDOWN
+	, SI5351C_CLK_POWERDOWN
+	, SI5351C_CLK_POWERDOWN | SI5351C_CLK_INT_MODE 
+	, SI5351C_CLK_POWERDOWN | SI5351C_CLK_INT_MODE
+	};
 	si5351c_write(data, sizeof(data));
 }
 
@@ -127,8 +136,11 @@ void si5351c_configure_pll_sources_for_xtal()
 /* MultiSynth NA (PLL1) */
 void si5351c_configure_pll1_multisynth()
 {
-	uint8_t data[] = { 26, 0x00, 0x01, 0x00, 0x0E, 0x00, 0x00, 0x00, 0x00 };
-	si5351c_write(data, sizeof(data));
+	//init plla and pllb to (0x0e00+512)/128*25mhz xtal = 800mhz -> int mode
+ 	uint8_t data[] = { 26, 0x00, 0x01, 0x00, 0x0E, 0x00, 0x00, 0x00, 0x00 };
+ 	si5351c_write(data, sizeof(data));
+	//~ data[0] =34;// pllb
+	//~ si5351c_write(data, sizeof(data));
 }
 
 void si5351c_configure_multisynth(const uint_fast8_t ms_number,
@@ -215,67 +227,25 @@ void si5351c_configure_clock_control()
 #endif
 
 #ifdef JAWBREAKER
-/*
- * Registers 16 through 23: CLKx Control
- * CLK0:
- *   CLK0_PDN=0 (powered up)
- *   MS0_INT=1 (integer mode)
- *   MS0_SRC=0 (PLLA as source for MultiSynth 0)
- *   CLK0_INV=0 (not inverted)
- *   CLK0_SRC=3 (MS0 as input source)
- *   CLK0_IDRV=3 (8mA)
- * CLK1:
- *   CLK1_PDN=0 (powered up)
- *   MS1_INT=1 (integer mode)
- *   MS1_SRC=0 (PLLA as source for MultiSynth 1)
- *   CLK1_INV=0 (not inverted)
- *   CLK1_SRC=2 (MS0 as input source)
- *   CLK1_IDRV=3 (8mA)
- * CLK2:
- *   CLK2_PDN=0 (powered up)
- *   MS2_INT=1 (integer mode)
- *   MS2_SRC=0 (PLLA as source for MultiSynth 2)
- *   CLK2_INV=0 (not inverted)
- *   CLK2_SRC=2 (MS0 as input source)
- *   CLK2_IDRV=3 (8mA)
- * CLK3:
- *   CLK3_PDN=0 (powered up)
- *   MS3_INT=1 (integer mode)
- *   MS3_SRC=0 (PLLA as source for MultiSynth 3)
- *   CLK3_INV=0 (inverted)
- *   CLK3_SRC=2 (MS0 as input source)
- *   CLK3_IDRV=3 (8mA)
- * CLK4:
- *   CLK4_PDN=0 (powered up)
- *   MS4_INT=1 (integer mode)
- *   MS4_SRC=0 (PLLA as source for MultiSynth 4)
- *   CLK4_INV=0 (not inverted)
- *   CLK4_SRC=3 (MS4 as input source)
- *   CLK4_IDRV=3 (8mA)
- * CLK5:
- *   CLK5_PDN=0 (powered up)
- *   MS5_INT=1 (integer mode)
- *   MS5_SRC=0 (PLLA as source for MultiSynth 5)
- *   CLK5_INV=0 (not inverted)
- *   CLK5_SRC=3 (MS5 as input source)
- *   CLK5_IDRV=3 (8mA)
- * CLK6: (not connected)
- *   CLK5_PDN=1 (powered down)
- *   MS5_INT=1 (integer mode)
- * CLK7: (not connected)
- *   CLK7_PDN=1 (powered down)
- *   MS7_INT=0 (fractional mode -- to support 12MHz to LPC)
- */
 void si5351c_configure_clock_control()
 {
-	uint8_t data[] = { 16, 0x4F, 0x4B, 0x4B, 0x4B, 0x4F, 0x4F, 0xC0, 0x80 };
+	uint8_t data[] = {16
+	,SI5351C_CLK_FRAC_MODE | SI5351C_CLK_PLL_SRC(SI5351C_CLK_PLL_SRC_A) | SI5351C_CLK_SRC(SI5351C_CLK_SRC_MULTISYNTH_SELF) | SI5351C_CLK_IDRV(SI5351C_CLK_IDRV_8MA)
+	,SI5351C_CLK_INT_MODE | SI5351C_CLK_PLL_SRC(SI5351C_CLK_PLL_SRC_A) | SI5351C_CLK_SRC(SI5351C_CLK_SRC_MULTISYNTH_0_4) | SI5351C_CLK_IDRV(SI5351C_CLK_IDRV_8MA)
+	,SI5351C_CLK_INT_MODE | SI5351C_CLK_PLL_SRC(SI5351C_CLK_PLL_SRC_A) | SI5351C_CLK_SRC(SI5351C_CLK_SRC_MULTISYNTH_0_4) | SI5351C_CLK_IDRV(SI5351C_CLK_IDRV_8MA)
+	,SI5351C_CLK_POWERDOWN /*not connected, clock out*/
+	,SI5351C_CLK_INT_MODE | SI5351C_CLK_PLL_SRC(SI5351C_CLK_PLL_SRC_A) | SI5351C_CLK_SRC(SI5351C_CLK_SRC_MULTISYNTH_SELF) | SI5351C_CLK_IDRV(SI5351C_CLK_IDRV_8MA)
+	,SI5351C_CLK_INT_MODE | SI5351C_CLK_PLL_SRC(SI5351C_CLK_PLL_SRC_A) | SI5351C_CLK_SRC(SI5351C_CLK_SRC_MULTISYNTH_SELF) | SI5351C_CLK_IDRV(SI5351C_CLK_IDRV_8MA)
+	,SI5351C_CLK_POWERDOWN | SI5351C_CLK_INT_MODE /*not connected, but: plla int mode*/
+	,SI5351C_CLK_POWERDOWN | SI5351C_CLK_INT_MODE /* pllb int mode*/| SI5351C_CLK_PLL_SRC(SI5351C_CLK_PLL_SRC_B) | SI5351C_CLK_SRC(SI5351C_CLK_SRC_MULTISYNTH_SELF) | SI5351C_CLK_IDRV(SI5351C_CLK_IDRV_8MA)
+	 };
 	si5351c_write(data, sizeof(data));
 }
 #endif
 
-/* Enable CLK outputs 0, 1, 2, 3, 4, 5 only. */
-void si5351c_enable_clock_outputs()
-{
-	uint8_t data[] = { 3, 0xC0 };
-	si5351c_write(data, sizeof(data));
-}
+/* Enable CLK outputs 0, 1, 2, 4, 5, ~7 only. */
+ void si5351c_enable_clock_outputs()
+ {
+	uint8_t data[] = { 3, 0xC8 };
+ 	si5351c_write(data, sizeof(data));
+ }
diff --git a/firmware/common/si5351c.h b/firmware/common/si5351c.h
index 8cd583ed..12f1dc3a 100644
--- a/firmware/common/si5351c.h
+++ b/firmware/common/si5351c.h
@@ -30,8 +30,31 @@ extern "C"
 
 #include <stdint.h>
 
+#define SI_INTDIV(x)  (x*128-512)
 #define SI5351C_I2C_ADDR (0x60 << 1)
 
+#define SI5351C_CLK_POWERDOWN	(1<<7)
+#define SI5351C_CLK_INT_MODE	(1<<6)
+#define SI5351C_CLK_FRAC_MODE	(0<<6)
+
+#define SI5351C_CLK_PLL_SRC(x)	(x<<5)
+#define SI5351C_CLK_PLL_SRC_A	0
+#define SI5351C_CLK_PLL_SRC_B	1
+
+#define SI5351C_CLK_INV			(1<<4)
+
+#define SI5351C_CLK_SRC(x)		(x<<2)
+#define SI5351C_CLK_SRC_XTAL			0
+#define SI5351C_CLK_SRC_CLKIN			1
+#define SI5351C_CLK_SRC_MULTISYNTH_0_4	2
+#define SI5351C_CLK_SRC_MULTISYNTH_SELF	3
+
+#define SI5351C_CLK_IDRV(x) (x<<0)
+#define SI5351C_CLK_IDRV_2MA 0
+#define SI5351C_CLK_IDRV_4MA 1
+#define SI5351C_CLK_IDRV_6MA 2
+#define SI5351C_CLK_IDRV_8MA 3
+
 void si5351c_disable_all_outputs();
 void si5351c_disable_oeb_pin_control();
 void si5351c_power_down_all_clocks();
diff --git a/firmware/hackrf_usb/hackrf_usb.c b/firmware/hackrf_usb/hackrf_usb.c
index 83059efa..e42fbb9e 100644
--- a/firmware/hackrf_usb/hackrf_usb.c
+++ b/firmware/hackrf_usb/hackrf_usb.c
@@ -67,6 +67,12 @@ typedef struct {
 
 set_freq_params_t set_freq_params;
 
+typedef struct {
+	float freq_mhz;
+} set_sample_r_params_t;
+
+set_sample_r_params_t set_sample_r_params;
+
 uint8_t switchctrl = 0;
 
 void update_switches(void)
@@ -696,6 +702,28 @@ usb_request_status_t usb_vendor_request_set_freq(
 	}
 }
 
+usb_request_status_t usb_vendor_request_set_fracrate(
+	usb_endpoint_t* const endpoint,
+	const usb_transfer_stage_t stage) 
+{
+	if (stage == USB_TRANSFER_STAGE_SETUP) 
+	{
+		usb_endpoint_schedule(endpoint->out, &set_sample_r_params, sizeof(set_sample_r_params_t));
+		return USB_REQUEST_STATUS_OK;
+	} else if (stage == USB_TRANSFER_STAGE_DATA) 
+	{
+		if( set_fracrate(set_sample_r_params.freq_mhz*2) ) 
+		{
+			usb_endpoint_schedule_ack(endpoint->in);
+			return USB_REQUEST_STATUS_OK;
+		}
+		return USB_REQUEST_STATUS_STALL;
+	} else
+	{
+		return USB_REQUEST_STATUS_OK;
+	}
+}
+
 usb_request_status_t usb_vendor_request_set_amp_enable(
 	usb_endpoint_t* const endpoint, const usb_transfer_stage_t stage)
 {
@@ -821,7 +849,8 @@ static const usb_request_handler_fn vendor_request_handler[] = {
 	usb_vendor_request_read_partid_serialno,
 	usb_vendor_request_set_lna_gain,
 	usb_vendor_request_set_vga_gain,
-	usb_vendor_request_set_txvga_gain
+	usb_vendor_request_set_txvga_gain,
+	usb_vendor_request_set_fracrate
 };
 
 static const uint32_t vendor_request_handler_count =
diff --git a/host/hackrf-tools/src/hackrf_si5351c.c b/host/hackrf-tools/src/hackrf_si5351c.c
index 398b7272..f9e86910 100644
--- a/host/hackrf-tools/src/hackrf_si5351c.c
+++ b/host/hackrf-tools/src/hackrf_si5351c.c
@@ -107,40 +107,56 @@ int dump_multisynth_config(hackrf_device* device, const uint_fast8_t ms_number)
 	uint_fast8_t reg_base;
 	uint16_t parameters[8];
 	uint32_t p1,p2,p3,r_div;
+	uint_fast8_t div_lut[] = {1,2,4,8,16,32,64,128};
 
-	reg_base = 42 + (ms_number * 8);
-	for(i=0; i<8; i++) {
-		uint_fast8_t reg_number = reg_base + i;
-		int result = hackrf_si5351c_read(device, reg_number, &parameters[i]);
-		if( result != HACKRF_SUCCESS ) {
-			return result;
-		}
-	}
-	
-	p1 =
-		  (parameters[2] & 0x03 << 16)
-		| (parameters[3] << 8)
-		| parameters[4]
-		;
-	p2 =
-		  (parameters[5] & 0x0F << 16)
-		| (parameters[6] << 8)
-		| parameters[7]
-		;
-	p3 =
-		  (parameters[5] & 0xF0 << 12)
-		| (parameters[0] << 8)
-		|  parameters[1]
-		;
-	r_div =
-		(parameters[2] >> 4) & 0x7
-		;
-		
-	printf("MS%d:", ms_number);
-	printf("\tp1 = %u\n", p1);
-	printf("\tp2 = %u\n", p2);
-	printf("\tp3 = %u\n", p3);
-	printf("\toutput divider = %u\n", 1 << r_div);
+    printf("MS%d:", ms_number);
+    if(ms_number <6){
+        reg_base = 42 + (ms_number * 8);
+        for(i=0; i<8; i++) {
+            uint_fast8_t reg_number = reg_base + i;
+            int result = hackrf_si5351c_read(device, reg_number, &parameters[i]);
+            if( result != HACKRF_SUCCESS ) {
+                return result;
+            }
+        }
+
+        p1 =
+              (parameters[2] & 0x03 << 16)
+            | (parameters[3] << 8)
+            | parameters[4]
+            ;
+        p2 =
+              (parameters[5] & 0x0F << 16)
+            | (parameters[6] << 8)
+            | parameters[7]
+            ;
+        p3 =
+              (parameters[5] & 0xF0 << 12)
+            | (parameters[0] << 8)
+            |  parameters[1]
+            ;
+        r_div =
+            (parameters[2] >> 4) & 0x7
+            ;
+
+        printf("\tp1 = %u\n", p1);
+        printf("\tp2 = %u\n", p2);
+        printf("\tp3 = %u\n", p3);
+    } else {
+        // MS6 and 7 are integer only
+        reg_base = 90;
+        for(i=0; i<3; i++) {
+            uint_fast8_t reg_number = reg_base + i;
+            int result = hackrf_si5351c_read(device, reg_number, &parameters[i]);
+            if( result != HACKRF_SUCCESS ) {
+                return result;
+            }
+        }
+
+        r_div = (ms_number == 6) ? parameters[2] & 0x7 : parameters[2] & 0x70 >> 4 ;
+		printf("\tp1_int = %u\n", (ms_number == 6) ? parameters[0] : parameters[1]);
+    }
+	printf("\toutput divider = %u\n", div_lut[r_div]);
 	
 	return HACKRF_SUCCESS;
 }
diff --git a/host/hackrf-tools/src/hackrf_transfer.c b/host/hackrf-tools/src/hackrf_transfer.c
index d1e2a35c..3423c8f0 100644
--- a/host/hackrf-tools/src/hackrf_transfer.c
+++ b/host/hackrf-tools/src/hackrf_transfer.c
@@ -318,7 +318,10 @@ static void usage() {
 	printf("\t-t <filename> # Transmit data from file.\n");
 	printf("\t[-f set_freq_hz] # Set Freq in Hz between [%lluMHz, %lluMHz[.\n", FREQ_MIN_HZ/FREQ_ONE_MHZ, FREQ_MAX_HZ/FREQ_ONE_MHZ);
 	printf("\t[-a set_amp] # Set Amp 1=Enable, 0=Disable.\n");
-	printf("\t[-s sample_rate_hz] # Set sample rate in Hz (5/10/12.5/16/20MHz, default %lldMHz).\n", DEFAULT_SAMPLE_RATE_HZ/FREQ_ONE_MHZ);
+	printf("\t[-l gain_db] # Set lna gain, 0-40dB, 8dB steps\n");
+	printf("\t[-i gain_db] # Set vga(if) gain, 0-62dB, 2dB steps\n");
+	printf("\t[-x gain_db] # Set TX vga gain, 0-47dB, 1dB steps\n");
+	printf("\t[-s sample_rate_hz] # Set sample rate in Hz (8/10/12.5/16/20MHz, default %lldMHz).\n", DEFAULT_SAMPLE_RATE_HZ/FREQ_ONE_MHZ);
 	printf("\t[-n num_samples] # Number of samples to transfer (default is unlimited).\n");
 	printf("\t[-b baseband_filter_bw_hz] # Set baseband filter bandwidth in MHz.\n\tPossible values: 1.75/2.5/3.5/5/5.5/6/7/8/9/10/12/14/15/20/24/28MHz, default < sample_rate_hz.\n" );
 }
@@ -359,8 +362,9 @@ int main(int argc, char** argv) {
 	int exit_code = EXIT_SUCCESS;
 	struct timeval t_end;
 	float time_diff;
+	unsigned int lna_gain=8, vga_gain=20, txvga_gain=0;
   
-	while( (opt = getopt(argc, argv, "wr:t:f:a:s:n:b:")) != EOF )
+	while( (opt = getopt(argc, argv, "wr:t:f:a:s:n:b:l:i:x:")) != EOF )
 	{
 		result = HACKRF_SUCCESS;
 		switch( opt ) 
@@ -389,6 +393,18 @@ int main(int argc, char** argv) {
 			result = parse_u32(optarg, &amp_enable);
 			break;
 
+		case 'l':
+			result = parse_u32(optarg, &lna_gain);
+			break;
+
+		case 'i':
+			result = parse_u32(optarg, &vga_gain);
+			break;
+
+		case 'x':
+			result = parse_u32(optarg, &txvga_gain);
+			break;
+
 		case 's':
 			sample_rate = true;
 			result = parse_u32(optarg, &sample_rate_hz);
@@ -592,9 +608,12 @@ int main(int argc, char** argv) {
 	}
 
 	if( transceiver_mode == TRANSCEIVER_MODE_RX ) {
-		result = hackrf_start_rx(device, rx_callback, NULL);
+		result = hackrf_set_vga_gain(device, vga_gain);
+		result |= hackrf_set_lna_gain(device, lna_gain);
+		result |= hackrf_start_rx(device, rx_callback, NULL);
 	} else {
-		result = hackrf_start_tx(device, tx_callback, NULL);
+		result = hackrf_set_txvga_gain(device, txvga_gain);
+		result |= hackrf_start_tx(device, tx_callback, NULL);
 	}
 	if( result != HACKRF_SUCCESS ) {
 		printf("hackrf_start_?x() failed: %s (%d)\n", hackrf_error_name(result), result);
diff --git a/host/libhackrf/CMakeLists.txt b/host/libhackrf/CMakeLists.txt
index 4bfc7d8d..9e376720 100644
--- a/host/libhackrf/CMakeLists.txt
+++ b/host/libhackrf/CMakeLists.txt
@@ -31,19 +31,56 @@ set(VERSION ${VERSION_STRING})
 set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/../cmake/modules)
 
 if(MSVC)
-set(THREADS_USE_PTHREADS_WIN32 true)
-find_package(Threads REQUIRED)
+	set(THREADS_USE_PTHREADS_WIN32 true)
 else()
-add_definitions(-Wall)
-set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu90")
+	add_definitions(-Wall)
+	set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=gnu90")
+
+	INCLUDE(TestBigEndian)
+	TEST_BIG_ENDIAN(BIGENDIAN)
+	if(${BIGENDIAN})
+		 add_definitions(-DBIG_ENDIAN)
+	endif(${BIGENDIAN})
 endif()
 find_package(USB1 REQUIRED)
-
+find_package(Threads REQUIRED)
 
 include_directories(${LIBUSB_INCLUDE_DIR} ${THREADS_PTHREADS_INCLUDE_DIR})
 
 add_subdirectory(src)
 
+########################################################################
+# Create Pkg Config File
+########################################################################
+FOREACH(inc ${LIBUSB_INCLUDE_DIR})
+    LIST(APPEND HACKRF_PC_CFLAGS "-I${inc}")
+ENDFOREACH(inc)
+
+# use space-separation format for the pc file
+STRING(REPLACE ";" " " HACKRF_PC_CFLAGS "${HACKRF_PC_CFLAGS}")
+STRING(REPLACE ";" " " HACKRF_PC_LIBS "${HACKRF_PC_LIBS}")
+
+# unset these vars to avoid hard-coded paths to cross environment
+IF(CMAKE_CROSSCOMPILING)
+    UNSET(HACKRF_PC_CFLAGS)
+    UNSET(HACKRF_PC_LIBS)
+ENDIF(CMAKE_CROSSCOMPILING)
+
+set(prefix ${CMAKE_INSTALL_PREFIX})
+set(exec_prefix \${prefix})
+set(libdir \${exec_prefix}/lib)
+set(includedir \${prefix}/include)
+
+CONFIGURE_FILE(
+    ${CMAKE_CURRENT_SOURCE_DIR}/libhackrf.pc.in
+    ${CMAKE_CURRENT_BINARY_DIR}/libhackrf.pc
+@ONLY)
+
+INSTALL(
+    FILES ${CMAKE_CURRENT_BINARY_DIR}/libhackrf.pc
+    DESTINATION lib/pkgconfig
+)
+
 ########################################################################
 # Create uninstall target
 ########################################################################
diff --git a/host/libhackrf/libhackrf.pc.in b/host/libhackrf/libhackrf.pc.in
new file mode 100644
index 00000000..5c9c18d4
--- /dev/null
+++ b/host/libhackrf/libhackrf.pc.in
@@ -0,0 +1,11 @@
+prefix=@prefix@
+exec_prefix=@exec_prefix@
+libdir=@libdir@
+includedir=@includedir@
+
+Name: HackRF Library
+Description: C Utility Library
+Version: @VERSION@
+Cflags: -I${includedir}/ @HACKRF_PC_CFLAGS@
+Libs: -L${libdir} -lhackrf
+Libs.private: @HACKRF_PC_LIBS@
diff --git a/host/libhackrf/src/hackrf.c b/host/libhackrf/src/hackrf.c
index 410f8f3b..e31fb714 100644
--- a/host/libhackrf/src/hackrf.c
+++ b/host/libhackrf/src/hackrf.c
@@ -33,6 +33,13 @@ typedef int bool;
 #define true 1
 #define false 0
 #endif
+
+#ifdef BIG_ENDIAN
+#define TO_LE(x) __builtin_bswap32(x)
+#else
+#define TO_LE(x) x
+#endif
+
 // TODO: Factor this into a shared #include so that firmware can use
 // the same values.
 typedef enum {
@@ -57,6 +64,7 @@ typedef enum {
 	HACKRF_VENDOR_REQUEST_SET_LNA_GAIN = 19,
 	HACKRF_VENDOR_REQUEST_SET_VGA_GAIN = 20,
 	HACKRF_VENDOR_REQUEST_SET_TXVGA_GAIN = 21,
+	HACKRF_VENDOR_REQUEST_SET_FRACRATE = 22,
 } hackrf_vendor_request;
 
 typedef enum {
@@ -731,8 +739,8 @@ int ADDCALL hackrf_set_freq(hackrf_device* device, const uint64_t freq_hz)
 	/* Convert Freq Hz 64bits to Freq MHz (32bits) & Freq Hz (32bits) */
 	l_freq_mhz = (uint32_t)(freq_hz / FREQ_ONE_MHZ);
 	l_freq_hz = (uint32_t)(freq_hz - (((uint64_t)l_freq_mhz) * FREQ_ONE_MHZ));
-	set_freq_params.freq_mhz = l_freq_mhz;
-	set_freq_params.freq_hz = l_freq_hz;
+	set_freq_params.freq_mhz = TO_LE(l_freq_mhz);
+	set_freq_params.freq_hz = TO_LE(l_freq_hz);
 	length = sizeof(set_freq_params_t);
 
 	result = libusb_control_transfer(
@@ -754,6 +762,42 @@ int ADDCALL hackrf_set_freq(hackrf_device* device, const uint64_t freq_hz)
 	}
 }
 
+
+typedef struct {
+	float freq_mhz;
+} set_fracrate_params_t;
+
+
+int ADDCALL hackrf_set_fracrate(hackrf_device* device, const float freq_mhz)
+{
+	uint32_t l_freq_mhz;
+	uint32_t l_freq_hz;
+	set_fracrate_params_t set_fracrate_params;
+	uint8_t length;
+	int result;
+	
+	set_fracrate_params.freq_mhz = TO_LE(freq_mhz);
+	length = sizeof(set_fracrate_params_t);
+
+	result = libusb_control_transfer(
+		device->usb_device,
+		LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE,
+		HACKRF_VENDOR_REQUEST_SET_FRACRATE,
+		0,
+		0,
+		(unsigned char*)&set_fracrate_params,
+		length,
+		0
+	);
+
+	if (result < length)
+	{
+		return HACKRF_ERROR_LIBUSB;
+	} else {
+		return HACKRF_SUCCESS;
+	}
+}
+
 int ADDCALL hackrf_set_amp_enable(hackrf_device* device, const uint8_t value)
 {
 	int result;
@@ -797,6 +841,14 @@ int ADDCALL hackrf_board_partid_serialno_read(hackrf_device* device, read_partid
 	{
 		return HACKRF_ERROR_LIBUSB;
 	} else {
+
+		read_partid_serialno->part_id[0] = TO_LE(read_partid_serialno->part_id[0]);
+		read_partid_serialno->part_id[0] = TO_LE(read_partid_serialno->part_id[1]);
+		read_partid_serialno->serial_no[0] = TO_LE(read_partid_serialno->serial_no[0]);
+		read_partid_serialno->serial_no[1] = TO_LE(read_partid_serialno->serial_no[1]);
+		read_partid_serialno->serial_no[2] = TO_LE(read_partid_serialno->serial_no[2]);
+		read_partid_serialno->serial_no[3] = TO_LE(read_partid_serialno->serial_no[3]);
+
 		return HACKRF_SUCCESS;
 	}
 }
@@ -804,6 +856,7 @@ int ADDCALL hackrf_board_partid_serialno_read(hackrf_device* device, read_partid
 int ADDCALL hackrf_set_lna_gain(hackrf_device* device, uint32_t value)
 {
 	int result;
+	uint8_t retval;
 	
 	if( value > 40 )
 	{
@@ -812,16 +865,16 @@ int ADDCALL hackrf_set_lna_gain(hackrf_device* device, uint32_t value)
 
 	result = libusb_control_transfer(
 		device->usb_device,
-		LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE,
+		LIBUSB_ENDPOINT_IN | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE,
 		HACKRF_VENDOR_REQUEST_SET_LNA_GAIN,
 		0,
 		value,
-		NULL,
-		0,
+		&retval,
+		1,
 		0
 	);
 
-	if( result != 0 )
+	if( result != 1 || !retval )
 	{
 		return HACKRF_ERROR_INVALID_PARAM;
 	} else {
@@ -832,6 +885,7 @@ int ADDCALL hackrf_set_lna_gain(hackrf_device* device, uint32_t value)
 int ADDCALL hackrf_set_vga_gain(hackrf_device* device, uint32_t value)
 {
 	int result;
+	uint8_t retval;
 	
 	if( value > 62 )
 	{
@@ -840,16 +894,16 @@ int ADDCALL hackrf_set_vga_gain(hackrf_device* device, uint32_t value)
 
 	result = libusb_control_transfer(
 		device->usb_device,
-		LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE,
+		LIBUSB_ENDPOINT_IN | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE,
 		HACKRF_VENDOR_REQUEST_SET_VGA_GAIN,
 		0,
 		value,
-		NULL,
-		0,
+		&retval,
+		1,
 		0
 	);
 
-	if( result != 0 )
+	if( result != 1 || !retval )
 	{
 		return HACKRF_ERROR_INVALID_PARAM;
 	} else {
@@ -860,6 +914,7 @@ int ADDCALL hackrf_set_vga_gain(hackrf_device* device, uint32_t value)
 int ADDCALL hackrf_set_txvga_gain(hackrf_device* device, uint32_t value)
 {
 	int result;
+	uint8_t retval;
 	
 	if( value > 47 )
 	{
@@ -868,16 +923,16 @@ int ADDCALL hackrf_set_txvga_gain(hackrf_device* device, uint32_t value)
 
 	result = libusb_control_transfer(
 		device->usb_device,
-		LIBUSB_ENDPOINT_OUT | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE,
+		LIBUSB_ENDPOINT_IN | LIBUSB_REQUEST_TYPE_VENDOR | LIBUSB_RECIPIENT_DEVICE,
 		HACKRF_VENDOR_REQUEST_SET_TXVGA_GAIN,
 		0,
 		value,
-		NULL,
-		0,
+		&retval,
+		1,
 		0
 	);
 
-	if( result != 0 )
+	if( result != 1 || !retval )
 	{
 		return HACKRF_ERROR_INVALID_PARAM;
 	} else {
@@ -894,7 +949,7 @@ static void* transfer_threadproc(void* arg)
 	while( (device->streaming) && (do_exit == false) )
 	{
 		error = libusb_handle_events_timeout(g_libusb_context, &timeout);
-		if( error != 0 )
+		if( (error != 0) && (error != LIBUSB_ERROR_INTERRUPTED) )
 		{
 			device->streaming = false;
 		}
diff --git a/host/libhackrf/src/hackrf.h b/host/libhackrf/src/hackrf.h
index 14968319..96d2dcf6 100644
--- a/host/libhackrf/src/hackrf.h
+++ b/host/libhackrf/src/hackrf.h
@@ -129,6 +129,7 @@ extern ADDAPI int ADDCALL hackrf_board_id_read(hackrf_device* device, uint8_t* v
 extern ADDAPI int ADDCALL hackrf_version_string_read(hackrf_device* device, char* version, uint8_t length);
 
 extern ADDAPI int ADDCALL hackrf_set_freq(hackrf_device* device, const uint64_t freq_hz);
+extern ADDAPI int ADDCALL hackrf_set_fracrate(hackrf_device* device, const float freq_mhz);
 
 /* external amp, bool on/off */
 extern ADDAPI int ADDCALL hackrf_set_amp_enable(hackrf_device* device, const uint8_t value);