diff --git a/libraries/Ethernet/src/Ethernet.cpp b/libraries/Ethernet/src/Ethernet.cpp
index 2e0f1a94f..0f6450a7a 100644
--- a/libraries/Ethernet/src/Ethernet.cpp
+++ b/libraries/Ethernet/src/Ethernet.cpp
@@ -1,12 +1,8 @@
 #include "Ethernet.h"
 
-#define SSID_MAX_LENGTH 32
-
 int arduino::EthernetClass::begin(uint8_t *mac, unsigned long timeout, unsigned long responseTimeout) {
   if (eth_if == nullptr) {
-    //Q: What is the callback for?
-    _initializerCallback();
-    if (eth_if == nullptr) return 0;
+    return 0;
   }
   eth_if->set_dhcp(true);
   return _begin(mac, timeout, responseTimeout);
@@ -51,6 +47,10 @@ int arduino::EthernetClass::begin(uint8_t *mac, IPAddress ip, IPAddress dns, IPA
 }
 
 int arduino::EthernetClass::begin(uint8_t *mac, IPAddress ip, IPAddress dns, IPAddress gateway, IPAddress subnet, unsigned long timeout, unsigned long responseTimeout) {
+  if(eth_if == nullptr) {
+    return 0;
+  }
+
   config(ip, dns, gateway, subnet);
 
   eth_if->set_dhcp(false);
@@ -68,6 +68,9 @@ void arduino::EthernetClass::end() {
 }
 
 EthernetLinkStatus arduino::EthernetClass::linkStatus() {
+  if(eth_if == nullptr) {
+    return LinkOFF;
+  }
   return (eth_if->get_connection_status() == NSAPI_STATUS_GLOBAL_UP ? LinkON : LinkOFF);
 }
 
@@ -77,7 +80,9 @@ EthernetHardwareStatus arduino::EthernetClass::hardwareStatus() {
 
 
 int arduino::EthernetClass::disconnect() {
-  eth_if->disconnect();
+  if(eth_if != nullptr) {
+    eth_if->disconnect();
+  }
   return 1;
 }
 
@@ -99,4 +104,4 @@ void arduino::EthernetClass::MACAddress(uint8_t *mac_address)
   macAddress(mac_address);
 }
 
-arduino::EthernetClass Ethernet;
+arduino::EthernetClass Ethernet(static_cast<EthernetInterface*>(EthInterface::get_default_instance()));
diff --git a/libraries/Ethernet/src/Ethernet.h b/libraries/Ethernet/src/Ethernet.h
index 2fc2ef240..8783d651c 100644
--- a/libraries/Ethernet/src/Ethernet.h
+++ b/libraries/Ethernet/src/Ethernet.h
@@ -50,21 +50,15 @@ enum {  // compatibility with Arduino ::maintain()
     DHCP_CHECK_REBIND_OK    = 4
 };
 
-typedef void *(*voidPrtFuncPtr)(void);
-
 class EthernetClass : public MbedSocketClass {
 
 public:
-  // Initialise the Ethernet shield to use the provided MAC address and
-  // gain the rest of the configuration through DHCP.
-  // Returns 0 if the DHCP configuration failed, and 1 if it succeeded
   EthernetClass(EthernetInterface *_if)
     : eth_if(_if){};
-  EthernetClass(){};
-
-  EthernetClass(voidPrtFuncPtr _cb)
-    : _initializerCallback(_cb){};
 
+  // Initialise the Ethernet shield to use the provided MAC address and
+  // gain the rest of the configuration through DHCP.
+  // Returns 0 if the DHCP configuration failed, and 1 if it succeeded
   int begin(uint8_t *mac = nullptr, unsigned long timeout = 60000, unsigned long responseTimeout = 4000);
   EthernetLinkStatus linkStatus();
   EthernetHardwareStatus hardwareStatus();
@@ -119,9 +113,7 @@ class EthernetClass : public MbedSocketClass {
   int _begin(uint8_t *mac, unsigned long timeout, unsigned long responseTimeout);
 
   volatile EthernetLinkStatus _currentNetworkStatus = Unknown;
-  EthernetInterface net;
-  EthernetInterface *eth_if = &net;
-  voidPrtFuncPtr _initializerCallback;
+  EthernetInterface *eth_if = nullptr;
   arduino::IPAddress ipAddressFromSocketAddress(SocketAddress socketAddress);
 };
 
diff --git a/libraries/GPS/src/GPS.h b/libraries/GPS/src/GPS.h
index 998430ecc..e02d5e9db 100644
--- a/libraries/GPS/src/GPS.h
+++ b/libraries/GPS/src/GPS.h
@@ -25,8 +25,6 @@
 
 namespace arduino {
 
-typedef void* (*voidPrtFuncPtr)(void);
-
 class GPSClass : public HardwareSerial {
 public:
 
diff --git a/libraries/GSM/src/GSM.h b/libraries/GSM/src/GSM.h
index a41e7692d..cf3652c26 100644
--- a/libraries/GSM/src/GSM.h
+++ b/libraries/GSM/src/GSM.h
@@ -65,8 +65,6 @@
 
 namespace arduino {
 
-typedef void* (*voidPrtFuncPtr)(void);
-
 class GSMClass : public MbedSocketClass {
 public:
 
diff --git a/libraries/WiFi/src/WiFi.h b/libraries/WiFi/src/WiFi.h
index 1dd01df61..ad650fb14 100644
--- a/libraries/WiFi/src/WiFi.h
+++ b/libraries/WiFi/src/WiFi.h
@@ -46,8 +46,6 @@ extern "C" {
 
 namespace arduino {
 
-typedef void* (*voidPrtFuncPtr)(void);
-
 class WiFiClass : public MbedSocketClass {
 public:
   static int16_t _state[MAX_SOCK_NUM];