diff --git a/src/PF1550.cpp b/src/PF1550.cpp
index fe8800c..f23c14f 100644
--- a/src/PF1550.cpp
+++ b/src/PF1550.cpp
@@ -43,12 +43,12 @@ PF1550::PF1550(PF1550_IO & io)
    PUBLIC MEMBER FUNCTIONS
  ******************************************************************************/
 
-int PF1550::begin()
+void PF1550::begin()
 {
   if (_debug) {
     _debug->println("PF1550 begin");
   }
-  return _control.begin();
+  _control.begin();
 }
 
 void PF1550::debug(Stream& stream)
diff --git a/src/PF1550.h b/src/PF1550.h
index 2d41571..436c1e8 100644
--- a/src/PF1550.h
+++ b/src/PF1550.h
@@ -49,7 +49,7 @@ class PF1550
 
   PF1550(PF1550_IO & io);
 
-  int begin();
+  void begin();
 
   void debug(Stream& stream);
 
diff --git a/src/PF1550/PF1550_Control.cpp b/src/PF1550/PF1550_Control.cpp
index 4a56f7c..53542e4 100644
--- a/src/PF1550/PF1550_Control.cpp
+++ b/src/PF1550/PF1550_Control.cpp
@@ -40,9 +40,9 @@ PF1550_Control::PF1550_Control(PF1550_IO & io)
    PUBLIC MEMBER FUNCTIONS
  ******************************************************************************/
 
-int PF1550_Control::begin()
+void PF1550_Control::begin()
 {
-  return _io.begin();
+  _io.begin();
 }
 
 void PF1550_Control::debug(Stream& stream)
diff --git a/src/PF1550/PF1550_Control.h b/src/PF1550/PF1550_Control.h
index 05b6082..b22df74 100644
--- a/src/PF1550/PF1550_Control.h
+++ b/src/PF1550/PF1550_Control.h
@@ -45,7 +45,7 @@ class PF1550_Control
   PF1550_Control(PF1550_IO & io);
 
 
-  int begin();
+  void begin();
   void debug(Stream& stream);
 
   void setBit  (Register const reg, uint8_t const bit_pos);
diff --git a/src/PF1550/PF1550_IO.cpp b/src/PF1550/PF1550_IO.cpp
index 334334b..be227d8 100644
--- a/src/PF1550/PF1550_IO.cpp
+++ b/src/PF1550/PF1550_IO.cpp
@@ -41,11 +41,11 @@ PF1550_IO::PF1550_IO(arduino::HardwareI2C * wire, uint8_t const i2c_addr)
    PUBLIC MEMBER FUNCTIONS
  ******************************************************************************/
 
-int PF1550_IO::begin()
+void PF1550_IO::begin()
 {
   _wire->begin();
   _wire->setClock(100000);
-  return derived_begin();
+  derived_begin();
 }
 
 void PF1550_IO::readRegister(Register const reg_addr, uint8_t * data)
diff --git a/src/PF1550/PF1550_IO.h b/src/PF1550/PF1550_IO.h
index caa2323..b55d551 100644
--- a/src/PF1550/PF1550_IO.h
+++ b/src/PF1550/PF1550_IO.h
@@ -50,7 +50,7 @@ class PF1550_IO
   void debug (Stream& stream) { _debug = &stream; }
 
 
-  int begin();
+  void begin();
 
   void readRegister (Register const reg_addr, uint8_t * data);
   void writeRegister(Register const reg_addr, uint8_t const data);
@@ -60,7 +60,7 @@ class PF1550_IO
 
 
 protected:
-  virtual int derived_begin() = 0;
+  virtual void derived_begin() = 0;
 
 private:
   arduino::HardwareI2C * _wire;
diff --git a/src/PF1550/PF1550_IO_C33.h b/src/PF1550/PF1550_IO_C33.h
index 3aa564f..1aa75cf 100644
--- a/src/PF1550/PF1550_IO_C33.h
+++ b/src/PF1550/PF1550_IO_C33.h
@@ -39,7 +39,7 @@ class PF1550_IO_C33 : public PF1550_IO
 
 
 protected:
-  virtual int derived_begin() override
+  virtual void derived_begin() override
   {
     /* Enable LED. */
     setBit(Register::CHARGER_LED_PWM, REG_LED_PWM_LED_EN_bp);
diff --git a/src/PF1550/PF1550_IO_Nicla_Vision.h b/src/PF1550/PF1550_IO_Nicla_Vision.h
index 3bdce52..95c916c 100644
--- a/src/PF1550/PF1550_IO_Nicla_Vision.h
+++ b/src/PF1550/PF1550_IO_Nicla_Vision.h
@@ -37,7 +37,7 @@ class PF1550_IO_Nicla_Vision : public PF1550_IO
 
 
 protected:
-  virtual int derived_begin() override { }
+  virtual void derived_begin() override { }
 };
 
 #endif /* PF1550_IO_NICLA_VISION_H_ */
diff --git a/src/PF1550/PF1550_IO_Portenta_H7.h b/src/PF1550/PF1550_IO_Portenta_H7.h
index 7e1a6f7..056d61e 100644
--- a/src/PF1550/PF1550_IO_Portenta_H7.h
+++ b/src/PF1550/PF1550_IO_Portenta_H7.h
@@ -37,7 +37,7 @@ class PF1550_IO_Portenta_H7 : public PF1550_IO
 
 
 protected:
-  virtual int derived_begin() override { }
+  virtual void derived_begin() override { }
 };
 
 #endif /* PF1550_IO_ENVIEH747_H_ */