diff --git a/src/libs/usb/USBDevice.cpp b/src/libs/usb/USBDevice.cpp
index a29f44e948..6e41cb8630 100644
--- a/src/libs/usb/USBDevice.cpp
+++ b/src/libs/usb/USBDevice.cpp
@@ -369,3 +369,11 @@ BUSBDevice::ControlTransfer(uint8 requestType, uint8 request, uint16 value,
 
 	return command.control.length;
 }
+
+
+// definition of reserved virtual functions
+void BUSBDevice::_ReservedUSBDevice1() {};
+void BUSBDevice::_ReservedUSBDevice2() {};
+void BUSBDevice::_ReservedUSBDevice3() {};
+void BUSBDevice::_ReservedUSBDevice4() {};
+void BUSBDevice::_ReservedUSBDevice5() {};
diff --git a/src/libs/usb/USBRoster.cpp b/src/libs/usb/USBRoster.cpp
index 5d40fa2cec..c2e96d2399 100644
--- a/src/libs/usb/USBRoster.cpp
+++ b/src/libs/usb/USBRoster.cpp
@@ -267,3 +267,11 @@ BUSBRoster::Stop()
 	((RosterLooper *)fLooper)->Stop();
 	fLooper = NULL;
 }
+
+
+// definition of reserved virtual functions
+void BUSBRoster::_ReservedUSBRoster1() {};
+void BUSBRoster::_ReservedUSBRoster2() {};
+void BUSBRoster::_ReservedUSBRoster3() {};
+void BUSBRoster::_ReservedUSBRoster4() {};
+void BUSBRoster::_ReservedUSBRoster5() {};