diff --git a/src/nunchuck/nunchuck.cxx b/src/nunchuck/nunchuck.cxx
index 4cd70010..8138dd4f 100644
--- a/src/nunchuck/nunchuck.cxx
+++ b/src/nunchuck/nunchuck.cxx
@@ -73,7 +73,7 @@ bool NUNCHUCK::writeByte(uint8_t reg, uint8_t byte)
   return true;
 }
 
-uint8_t NUNCHUCK::readBytes(uint8_t reg, uint8_t *buffer, unsigned int len)
+int NUNCHUCK::readBytes(uint8_t reg, uint8_t *buffer, int len)
 {
   if (!len || !buffer)
     return 0;
diff --git a/src/nunchuck/nunchuck.h b/src/nunchuck/nunchuck.h
index 5ff36233..24d509fa 100644
--- a/src/nunchuck/nunchuck.h
+++ b/src/nunchuck/nunchuck.h
@@ -95,7 +95,7 @@ namespace upm {
      * @param len Number of bytes to read
      * @return Number of bytes read
      */
-    uint8_t readBytes(uint8_t reg, uint8_t *buffer, unsigned int len);
+    int readBytes(uint8_t reg, uint8_t *buffer, int len);
 
     /**
      * Initializes the controller. Here, we disable encryption after