diff --git a/src/hal/hal.cpp b/src/hal/hal.cpp
index fba4ce10..15c7dec3 100644
--- a/src/hal/hal.cpp
+++ b/src/hal/hal.cpp
@@ -141,33 +141,37 @@ static void hal_spi_init () {
     SPI.begin();
 }
 
-void hal_pin_nss (u1_t val) {
-    if (!val) {
-        uint32_t spi_freq;
+static void hal_spi_trx(u1_t cmd, u1_t* buf, int len, u1_t is_read) {
+    uint32_t spi_freq;
+    u1_t nss = plmic_pins->nss;
 
-        if ((spi_freq = plmic_pins->spi_freq) == 0)
-            spi_freq = LMIC_SPI_FREQ;
+    if ((spi_freq = plmic_pins->spi_freq) == 0)
+        spi_freq = LMIC_SPI_FREQ;
 
-        SPISettings settings(spi_freq, MSBFIRST, SPI_MODE0);
-        SPI.beginTransaction(settings);
-    } else {
-        SPI.endTransaction();
+    SPISettings settings(spi_freq, MSBFIRST, SPI_MODE0);
+    SPI.beginTransaction(settings);
+    digitalWrite(nss, 0);
+
+    SPI.transfer(cmd);
+
+    for (u1_t i = 0; i < len; i++) {
+        u1_t* p = buf + i;
+        u1_t data = is_read ? 0x00 : *p;
+        data = SPI.transfer(data);
+        if (is_read)
+            *p = data;
     }
 
-    //Serial.println(val?">>":"<<");
-    digitalWrite(plmic_pins->nss, val);
+    digitalWrite(nss, 1);
+    SPI.endTransaction();
+}
+
+void hal_spi_write(u1_t cmd, const u1_t* buf, int len) {
+    hal_spi_trx(cmd, (u1_t*)buf, len, 0);
 }
 
-// perform SPI transaction with radio
-u1_t hal_spi (u1_t out) {
-    u1_t res = SPI.transfer(out);
-/*
-    Serial.print(">");
-    Serial.print(out, HEX);
-    Serial.print("<");
-    Serial.println(res, HEX);
-    */
-    return res;
+void hal_spi_read(u1_t cmd, u1_t* buf, int len) {
+    hal_spi_trx(cmd, buf, len, 1);
 }
 
 // -----------------------------------------------------------------------------
diff --git a/src/lmic/hal.h b/src/lmic/hal.h
index 51866d9a..a4256b1c 100644
--- a/src/lmic/hal.h
+++ b/src/lmic/hal.h
@@ -43,11 +43,6 @@ void hal_init (void);
  */
 void hal_init_ex (const void *pContext);
 
-/*
- * drive radio NSS pin (0=low, 1=high).
- */
-void hal_pin_nss (u1_t val);
-
 /*
  * drive radio RX/TX pins (0=rx, 1=tx).
  */
@@ -59,11 +54,18 @@ void hal_pin_rxtx (u1_t val);
 void hal_pin_rst (u1_t val);
 
 /*
- * perform 8-bit SPI transaction with radio.
- *   - write given byte 'outval'
- *   - read byte and return value
+ * Perform SPI write transaction with radio chip
+ *   - write the command byte 'cmd'
+ *   - write 'len' bytes out of 'buf'
+ */
+void hal_spi_write(u1_t cmd, const u1_t* buf, int len);
+
+/*
+ * Perform SPI read transaction with radio chip
+ *   - write the command byte 'cmd'
+ *   - read 'len' bytes into 'buf'
  */
-u1_t hal_spi (u1_t outval);
+void hal_spi_read(u1_t cmd, u1_t* buf, int len);
 
 /*
  * disable all CPU interrupts.
diff --git a/src/lmic/radio.c b/src/lmic/radio.c
index 60ec6336..0b5c28c4 100644
--- a/src/lmic/radio.c
+++ b/src/lmic/radio.c
@@ -290,36 +290,21 @@ static u1_t randbuf[16];
 
 
 static void writeReg (u1_t addr, u1_t data ) {
-    hal_pin_nss(0);
-    hal_spi(addr | 0x80);
-    hal_spi(data);
-    hal_pin_nss(1);
+    hal_spi_write(addr | 0x80, &data, 1);
 }
 
 static u1_t readReg (u1_t addr) {
-    hal_pin_nss(0);
-    hal_spi(addr & 0x7F);
-    u1_t val = hal_spi(0x00);
-    hal_pin_nss(1);
-    return val;
+    u1_t buf[1];
+    hal_spi_read(addr & 0x7f, buf, 1);
+    return buf[0];
 }
 
 static void writeBuf (u1_t addr, xref2u1_t buf, u1_t len) {
-    hal_pin_nss(0);
-    hal_spi(addr | 0x80);
-    for (u1_t i=0; i<len; i++) {
-        hal_spi(buf[i]);
-    }
-    hal_pin_nss(1);
+    hal_spi_write(addr | 0x80, buf, len);
 }
 
 static void readBuf (u1_t addr, xref2u1_t buf, u1_t len) {
-    hal_pin_nss(0);
-    hal_spi(addr & 0x7F);
-    for (u1_t i=0; i<len; i++) {
-        buf[i] = hal_spi(0x00);
-    }
-    hal_pin_nss(1);
+    hal_spi_read(addr & 0x7f, buf, len);
 }
 
 static void opmode (u1_t mode) {