diff --git a/platform/esb/dev/tr1001-gcr.c b/platform/esb/dev/tr1001-gcr.c
index a58d7f78f..ebe41fff3 100644
--- a/platform/esb/dev/tr1001-gcr.c
+++ b/platform/esb/dev/tr1001-gcr.c
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * @(#)$Id: tr1001-gcr.c,v 1.10 2007/10/25 09:30:39 adamdunkels Exp $
+ * @(#)$Id: tr1001-gcr.c,v 1.11 2007/11/19 09:50:54 adamdunkels Exp $
  */
 /**
  * \addtogroup esb
@@ -645,7 +645,7 @@ prepare_transmission(int synchbytes)
 }
 /*---------------------------------------------------------------------------*/
 int
-tr1001_send(const u8_t *packet, u16_t len)
+tr1001_send(const void *packet, unsigned short len)
 {
   int i;
   u16_t crc16;
@@ -671,7 +671,7 @@ tr1001_send(const u8_t *packet, u16_t len)
 
   /* Send packet data. */
   for(i = 0; i < len; ++i) {
-    crc16 = sendx_crc16(packet[i], crc16);
+    crc16 = sendx_crc16(((u8_t *)packet)[i], crc16);
   }
 
   /* Send CRC */
@@ -705,8 +705,8 @@ tr1001_send(const u8_t *packet, u16_t len)
   return 0;
 }
 /*---------------------------------------------------------------------------*/
-u16_t
-tr1001_read(u8_t *buf, u16_t bufsize)
+int
+tr1001_read(void *buf, unsigned short bufsize)
 {
   unsigned short tmplen;
 
diff --git a/platform/esb/dev/tr1001.h b/platform/esb/dev/tr1001.h
index 82f014968..87f24aaea 100644
--- a/platform/esb/dev/tr1001.h
+++ b/platform/esb/dev/tr1001.h
@@ -28,7 +28,7 @@
  *
  * This file is part of the Contiki operating system.
  *
- * @(#)$Id: tr1001.h,v 1.5 2007/08/07 11:11:20 nifi Exp $
+ * @(#)$Id: tr1001.h,v 1.6 2007/11/19 09:50:54 adamdunkels Exp $
  */
 #ifndef __TR1001_H__
 #define __TR1001_H__
@@ -114,7 +114,7 @@ void tr1001_set_numrexmit(unsigned char acks);
  * This function should normally not be called from user
  * programs. Rather, the uIP TCP/IP stack should be used.
  */
-int tr1001_send(const u8_t *packet, u16_t len);
+int tr1001_send(const void *packet, unsigned short len);
 
 /**
  * Check if an incoming packet has been received.
@@ -126,7 +126,7 @@ int tr1001_send(const u8_t *packet, u16_t len);
  * \return The length of the received packet, or 0 if no packet has
  * been received.
  */
-u16_t tr1001_read(u8_t *buf, u16_t bufsize);
+int tr1001_read(void *buf, unsigned short bufsize);
 
 extern unsigned char tr1001_rxbuf[];
 extern volatile unsigned char tr1001_rxstate;