diff --git a/atusb/fw/board_app.c b/atusb/fw/board_app.c
index cbbbf84..d996593 100644
--- a/atusb/fw/board_app.c
+++ b/atusb/fw/board_app.c
@@ -157,8 +157,8 @@ uint8_t irq_serial;
 ISR(INT0_vect)
 {
 	if (mac_irq) {
-		mac_irq();
-		return;
+		if (mac_irq())
+			return;
 	}
 	if (eps[1].state == EP_IDLE) {
 		led(1);
diff --git a/atusb/fw/mac.c b/atusb/fw/mac.c
index 51681c0..a5ea8d2 100644
--- a/atusb/fw/mac.c
+++ b/atusb/fw/mac.c
@@ -20,7 +20,7 @@
 #include "mac.h"
 
 
-void (*mac_irq)(void) = NULL;
+int (*mac_irq)(void) = NULL;
 
 
 static uint8_t rx_buf[MAX_PSDU+2]; /* PHDR+payload+LQ */
@@ -51,35 +51,30 @@ static void reg_write(uint8_t reg, uint8_t value)
 }
 
 
-static void handle_irq(void)
+static int handle_irq(void)
 {
 	uint8_t irq;
 	uint8_t size, i;
 
-	irq = reg_read(REG_IRQ_STATUS);
-	if (!(irq & IRQ_TRX_END))
-		return;
-
-	/*
-	 * @@@ we probably also have to handle at least IRQ_PLL_UNLOCK, because
-	 * a PLL unlock should cause a transition out of BUSY_TX without
-	 * TRX_END.
-	 */
 	if (txing) {
 		txing = 0;
-		return;
+		return 0;
 	}
 
+	irq = reg_read(REG_IRQ_STATUS);
+	if (!(irq & IRQ_TRX_END))
+		return 1;
+
 	/* unlikely */
 	if (eps[1].state != EP_IDLE)
-		return;
+		return 1;
 
 	spi_begin();
 	spi_send(AT86RF230_BUF_READ);
 	size = spi_recv();
 	if (size & 0x80) {
 		spi_end();
-		return;
+		return 1;
 	}
 
 	rx_buf[0] = size;
@@ -87,6 +82,7 @@ static void handle_irq(void)
 		rx_buf[i+1] = spi_recv();
 	spi_end();
 	usb_send(&eps[1], rx_buf, size+2, NULL, NULL);
+	return 1;
 }
 
 
diff --git a/atusb/fw/mac.h b/atusb/fw/mac.h
index a04e015..b75833e 100644
--- a/atusb/fw/mac.h
+++ b/atusb/fw/mac.h
@@ -16,7 +16,7 @@
 #include <stdint.h>
 
 
-extern void (*mac_irq)(void);
+extern int (*mac_irq)(void);
 
 int mac_rx(int on);
 int mac_tx(uint16_t flags, uint16_t len);
diff --git a/tools/include/atrf.h b/tools/include/atrf.h
index 70d0320..4917a43 100644
--- a/tools/include/atrf.h
+++ b/tools/include/atrf.h
@@ -57,4 +57,10 @@ uint8_t atrf_sram_read(struct atrf_dsc *dsc, uint8_t addr);
 
 int atrf_interrupt_wait(struct atrf_dsc *dsc, int timeout_ms);
 
+/* HardMAC operations */
+
+void atrf_rx_mode(struct atrf_dsc *dsc, int on);
+int atrf_rx(struct atrf_dsc *dsc, void *buf, int size, uint8_t *lqi);
+void atrf_tx(struct atrf_dsc *dsc, const void *buf, int size);
+
 #endif /* !ATRF_H */
diff --git a/tools/lib/atrf.c b/tools/lib/atrf.c
index 57371e4..1ea295a 100644
--- a/tools/lib/atrf.c
+++ b/tools/lib/atrf.c
@@ -322,3 +322,25 @@ int atrf_interrupt_wait(struct atrf_dsc *dsc, int timeout_ms)
 {
 	return dsc->driver->interrupt_wait(dsc->handle, timeout_ms);
 }
+
+
+void atrf_rx_mode(struct atrf_dsc *dsc, int on)
+{
+	if (dsc->driver->rx_mode)
+		dsc->driver->rx_mode(dsc->handle, on);
+}
+
+
+int atrf_rx(struct atrf_dsc *dsc, void *buf, int size, uint8_t *lqi)
+{
+	if (!dsc->driver->rx)
+		return 0;
+	return dsc->driver->rx(dsc->handle, buf, size, lqi);
+}
+
+
+void atrf_tx(struct atrf_dsc *dsc, const void *buf, int size)
+{
+	if (dsc->driver->tx)
+		dsc->driver->tx(dsc->handle, buf, size);
+}
diff --git a/tools/lib/driver.h b/tools/lib/driver.h
index c82c46b..b07f2f7 100644
--- a/tools/lib/driver.h
+++ b/tools/lib/driver.h
@@ -36,6 +36,9 @@ struct atrf_driver {
 	void (*sram_write)(void *dsc, uint8_t addr, uint8_t value);
 	uint8_t (*sram_read)(void *dsc, uint8_t addr);
 	int (*interrupt_wait)(void *dsc, int timeout_ms);
+	void (*rx_mode)(void *dsc, int on);
+	int (*rx)(void *dsc, void *buf, int size, uint8_t *lqi);
+	void (*tx)(void *dsc, const void *buf, int size);
 };