diff --git a/targets/ARCH/COMMON/common_lib.c b/targets/ARCH/COMMON/common_lib.c
index c4f4e3ead5..08daf58cf7 100644
--- a/targets/ARCH/COMMON/common_lib.c
+++ b/targets/ARCH/COMMON/common_lib.c
@@ -43,16 +43,31 @@
 //#include "targets/RT/USER/lte-softmodem.h"
 #include "executables/softmodem-common.h"
 
-char *get_devname(int devtype) {
-char *devnames[MAX_RF_DEV_TYPE]=DEVTYPE_NAMES;
+const char* devtype_names[MAX_RF_DEV_TYPE] = {
+  "",
+  "EXMIMO",
+  "USRP B200",
+  "USRP X300",
+  "USRP N300",
+  "USRP X400",
+  "BLADERF",
+  "LMSSDR",
+  "IRIS",
+  "No HW",
+  "ADRV9371_ZC706",
+  "UEDv2",
+  "RFSIMULATOR"
+};
+
+const char *get_devname(int devtype) {
   if (devtype < MAX_RF_DEV_TYPE && devtype !=MIN_RF_DEV_TYPE )
-  	  return devnames[devtype];
+    return devtype_names[devtype];
   return "none";
 }
 
 int set_device(openair0_device *device)
 {
-  char *devname = get_devname(device->type);
+  const char *devname = get_devname(device->type);
     if (strcmp(devname,"none") != 0) {
       LOG_I(HW,"[%s] has loaded %s device.\n",((device->host_type == RAU_HOST) ? "RAU": "RRU"),devname);
     } else {
diff --git a/targets/ARCH/COMMON/common_lib.h b/targets/ARCH/COMMON/common_lib.h
index 0c71a9999a..38a7b0fa67 100644
--- a/targets/ARCH/COMMON/common_lib.h
+++ b/targets/ARCH/COMMON/common_lib.h
@@ -92,6 +92,8 @@ typedef enum {
   USRP_X300_DEV,
   /*!\brief device is USRP N300/N310*/
   USRP_N300_DEV,
+  /*!\brief device is USRP X400/X410*/
+  USRP_X400_DEV,
   /*!\brief device is BLADE RF*/
   BLADERF_DEV,
   /*!\brief device is LMSSDR (SoDeRa)*/
@@ -107,7 +109,9 @@ typedef enum {
   RFSIMULATOR,
   MAX_RF_DEV_TYPE
 } dev_type_t;
-#define DEVTYPE_NAMES {"","EXMIMO","USRP B200","USRP X300","USRP N300","BLADERF","LMSSDR","IRIS","No HW","ADRV9371_ZC706","UEDv2", "RFSIMULATOR"} 
+/* list of names of devices, needs to match dev_type_t */
+extern const char* devtype_names[MAX_RF_DEV_TYPE];
+
 /*!\brief transport protocol types
  */
 typedef enum {
@@ -535,7 +539,7 @@ extern "C"
 
 
 /*! \brief get device name from device type */
-char *get_devname(int devtype);
+const char *get_devname(int devtype);
 /*! \brief Initialize openair RF target. It returns 0 if OK */
 int openair0_device_load(openair0_device *device, openair0_config_t *openair0_cfg);
 /*! \brief Initialize transport protocol . It returns 0 if OK */
diff --git a/targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp b/targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp
index e3b06a6438..4259304643 100644
--- a/targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp
+++ b/targets/ARCH/USRP/USERSPACE/LIB/usrp_lib.cpp
@@ -273,18 +273,20 @@ static int sync_to_gps(openair0_device *device) {
 static int trx_usrp_start(openair0_device *device) {
   usrp_state_t *s = (usrp_state_t *)device->priv;
 
-  // setup GPIO for TDD, GPIO(4) = ATR_RX
-  //set data direction register (DDR) to output
-  s->usrp->set_gpio_attr("FP0", "DDR", 0xfff, 0xfff);
-  //set lower 7 bits to be controlled automatically by ATR (the rest 5 bits are controlled manually)
-  s->usrp->set_gpio_attr("FP0", "CTRL", 0x7f,0xfff);
-  //set pins 4 (RX_TX_Switch) and 6 (Shutdown PA) to 1 when the radio is only receiving (ATR_RX)
-  s->usrp->set_gpio_attr("FP0", "ATR_RX", (1<<4)|(1<<6), 0x7f);
-  // set pin 5 (Shutdown LNA) to 1 when the radio is transmitting and receiveing (ATR_XX)
-  // (we use full duplex here, because our RX is on all the time - this might need to change later)
-  s->usrp->set_gpio_attr("FP0", "ATR_XX", (1<<5), 0x7f);
-  // set the output pins to 1
-  s->usrp->set_gpio_attr("FP0", "OUT", 7<<7, 0xf80);
+  if (device->type != USRP_X400_DEV) {
+    // setup GPIO for TDD, GPIO(4) = ATR_RX
+    //set data direction register (DDR) to output
+    s->usrp->set_gpio_attr("FP0", "DDR", 0xfff, 0xfff);
+    //set lower 7 bits to be controlled automatically by ATR (the rest 5 bits are controlled manually)
+    s->usrp->set_gpio_attr("FP0", "CTRL", 0x7f,0xfff);
+    //set pins 4 (RX_TX_Switch) and 6 (Shutdown PA) to 1 when the radio is only receiving (ATR_RX)
+    s->usrp->set_gpio_attr("FP0", "ATR_RX", (1<<4)|(1<<6), 0x7f);
+    // set pin 5 (Shutdown LNA) to 1 when the radio is transmitting and receiveing (ATR_XX)
+    // (we use full duplex here, because our RX is on all the time - this might need to change later)
+    s->usrp->set_gpio_attr("FP0", "ATR_XX", (1<<5), 0x7f);
+    // set the output pins to 1
+    s->usrp->set_gpio_attr("FP0", "OUT", 7<<7, 0xf80);
+  }
 
   s->wait_for_first_pps = 1;
   s->rx_count = 0;
@@ -847,7 +849,7 @@ rx_gain_calib_table_t calib_table_x310[] = {
   {-1,0}
 };
 
-/*! \brief USRPB210 RX calibration table */
+/*! \brief USRPn3xf RX calibration table */
 rx_gain_calib_table_t calib_table_n310[] = {
   {3500000000.0,0.0},
   {2660000000.0,0.0},
@@ -857,6 +859,16 @@ rx_gain_calib_table_t calib_table_n310[] = {
   {-1,0}
 };
 
+/*! \brief Empty RX calibration table */
+rx_gain_calib_table_t calib_table_none[] = {
+  {3500000000.0,0.0},
+  {2660000000.0,0.0},
+  {2300000000.0,0.0},
+  {1880000000.0,0.0},
+  {816000000.0, 0.0},
+  {-1,0}
+};
+
 
 /*! \brief Set RX gain offset
  * \param openair0_cfg RF frontend parameters set by application
@@ -1011,7 +1023,9 @@ extern "C" {
       device->type=USRP_N300_DEV;
       usrp_master_clock = 122.88e6;
       args += boost::str(boost::format(",master_clock_rate=%f") % usrp_master_clock);
-      //args += ", send_buff_size=33554432";
+
+      if ( 0 != system("sysctl -w net.core.rmem_max=62500000 net.core.wmem_max=62500000") )
+        LOG_W(HW,"Can't set kernel parameters for N3x0\n");
     }
 
     if (device_adds[0].get("type") == "x300") {
@@ -1025,6 +1039,13 @@ extern "C" {
         LOG_W(HW,"Can't set kernel parameters for X3xx\n");
     }
 
+    if (device_adds[0].get("type") == "x4xx") {
+      printf("Found USRP x400\n");
+      device->type = USRP_X400_DEV;
+      usrp_master_clock = 245.76e6;
+      args += boost::str(boost::format(",master_clock_rate=%f") % usrp_master_clock);
+    }
+
     s->usrp = uhd::usrp::multi_usrp::make(args);
 
     if (args.find("clock_source")==std::string::npos) {
@@ -1103,8 +1124,13 @@ extern "C" {
     std::cerr << "-- Using calibration table: calib_table_n310" << std::endl;
   }
 
+  if (device->type == USRP_X400_DEV) {
+    openair0_cfg[0].rx_gain_calib_table = calib_table_none;
+    std::cerr << "-- Using calibration table: calib_table_none" << std::endl;
+  }
 
-  if (device->type==USRP_N300_DEV || device->type==USRP_X300_DEV) {
+
+  if (device->type==USRP_N300_DEV || device->type==USRP_X300_DEV || device->type==USRP_X400_DEV) {
     LOG_I(HW,"%s() sample_rate:%u\n", __FUNCTION__, (int)openair0_cfg[0].sample_rate);
 
     switch ((int)openair0_cfg[0].sample_rate) {