diff --git a/include/sta/bus/i2c/device.hpp b/include/sta/bus/i2c/device.hpp
index 88485b3..71552fc 100644
--- a/include/sta/bus/i2c/device.hpp
+++ b/include/sta/bus/i2c/device.hpp
@@ -18,7 +18,7 @@ namespace sta
          * @param intf      %I2C hardware interface
          * @param csPin     The peripheral's address.
          */
-        I2CDevice(I2C * intf, int address, bool master=false, bool blocking=true);
+        I2CDevice(I2C * intf, int address, bool master=true, bool blocking=true);
 
     protected:
         void select() override;
diff --git a/include/sta/bus/interface.hpp b/include/sta/bus/interface.hpp
index a26151a..f5bbd9b 100644
--- a/include/sta/bus/interface.hpp
+++ b/include/sta/bus/interface.hpp
@@ -78,7 +78,7 @@ namespace sta
         bool isAquired();
     private:
         Mutex * mutex_;
-        bool    aquired_ = false;
+        bool    acquired_ = false;
     };
 } // namespace sta
 
diff --git a/include/sta/devices/raspi/bus/i2c.hpp b/include/sta/devices/raspi/bus/i2c.hpp
index d2573ac..b16449c 100644
--- a/include/sta/devices/raspi/bus/i2c.hpp
+++ b/include/sta/devices/raspi/bus/i2c.hpp
@@ -42,7 +42,8 @@ namespace sta
 
     class RaspiI2CDevice : public I2CDevice
     {
-        RaspiI2CDevice(RaspiI2C * intf, uint16_t address_10bit, Mutex* mutex=nullptr, bool master=false, bool blocking=true);
+    public:
+        RaspiI2CDevice(RaspiI2C * intf, uint16_t address_10bit, bool master=true, bool blocking=true);
     };
 } // namespace sta
 
diff --git a/src/bus/interface.cpp b/src/bus/interface.cpp
index 627e863..d32292d 100644
--- a/src/bus/interface.cpp
+++ b/src/bus/interface.cpp
@@ -12,18 +12,18 @@ namespace sta
 
     void Interface::acquire()
     {
-        if (mutex_ != nullptr)
-            mutex_->acquire();
+        mutex_->acquire();
+        acquired_ = true;
     }
 
     void Interface::release()
     {
-        if (mutex_ != nullptr)
-            mutex_->release();
+        mutex_->release();
+        acquired_ = false;
     }
 
     bool Interface::isAquired()
     {
-        return aquired_;
+        return acquired_;
     }
 } // namespace sta
diff --git a/src/devices/raspi/bus/i2c.cpp b/src/devices/raspi/bus/i2c.cpp
index be270c6..689d7df 100644
--- a/src/devices/raspi/bus/i2c.cpp
+++ b/src/devices/raspi/bus/i2c.cpp
@@ -3,6 +3,7 @@
 #ifdef STA_PLATFORM_RASPI
 
 #include <sta/debug/assert.hpp>
+#include <sta/debug/debug.hpp>
 
 #include <cstdlib>
 #include <string.h>
@@ -11,6 +12,7 @@
 #include <linux/i2c-dev.h>
 #include <sys/ioctl.h>
 #include <fcntl.h>
+#include <errno.h>
 #include <unistd.h>
 
 
@@ -41,21 +43,33 @@ namespace sta
     {
         STA_ASSERT(open_);
 
-        write(i2cfd_, &value, 1);
+        ssize_t n_out = write(i2cfd_, &value, 1);
+
+        if (n_out < 0)
+        {
+            STA_DEBUG_PRINT("Transfer of single byte failed: ");
+            STA_DEBUG_PRINTLN(strerror(errno));
+        }
+
+        STA_ASSERT(n_out == 1);
     }
 
     void RaspiI2C::transfer16(uint16_t value)
     {
         STA_ASSERT(open_);
 
-        write(i2cfd_, &value, 2);
+        ssize_t n_out = write(i2cfd_, &value, 2);
+
+        STA_ASSERT(n_out == 2);
     }
 
     void RaspiI2C::transfer(const uint8_t * buffer, size_t size)
     {
         STA_ASSERT(open_);
 
-        write(i2cfd_, buffer, size);
+        ssize_t n_out = write(i2cfd_, buffer, size);
+
+        STA_ASSERT(n_out == size);
     }
 
     void RaspiI2C::transfer(const uint8_t * txBuffer, uint8_t * rxBuffer, size_t size)
@@ -83,7 +97,9 @@ namespace sta
         uint8_t *buffer = new uint8_t[count];
         memset(buffer, value, count);
 
-        write(i2cfd_, buffer, count);
+        ssize_t n_out = write(i2cfd_, buffer, count);
+
+        STA_ASSERT(n_out == count);
 
         delete [] buffer; 
     }
@@ -100,6 +116,8 @@ namespace sta
         open_ = true;
 
         STA_ASSERT(i2cfd_ >= 0);
+
+        STA_DEBUG_PRINTLN("Successfully opened file");
     }
 
     void RaspiI2C::release()
@@ -111,8 +129,8 @@ namespace sta
         I2C::release();
     }
 
-    RaspiI2CDevice::RaspiI2CDevice(RaspiI2C * intf, uint16_t address_10bit, Mutex* mutex, bool master, bool blocking) 
-        : I2CDevice { intf, address_10bit }
+    RaspiI2CDevice::RaspiI2CDevice(RaspiI2C * intf, uint16_t address_10bit, bool master, bool blocking) 
+        : I2CDevice { intf, address_10bit, master, blocking }
     {
         
     }