diff --git a/src/WiFiStorage.cpp b/src/WiFiStorage.cpp
index 9d2ea4b7..9d3d13ea 100644
--- a/src/WiFiStorage.cpp
+++ b/src/WiFiStorage.cpp
@@ -1,3 +1,22 @@
+/*
+  WiFiStorage.cpp - Library for Arduino boards based on NINA wifi module.
+  Copyright (c) 2018 Arduino SA. All rights reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
 #include "WiFiStorage.h"
 
 WiFiStorageFile WiFiStorageClass::open(const char *filename) {
diff --git a/src/WiFiStorage.h b/src/WiFiStorage.h
index 2479c44c..72e1975f 100644
--- a/src/WiFiStorage.h
+++ b/src/WiFiStorage.h
@@ -1,3 +1,25 @@
+/*
+  WiFiStorage.h - Library for Arduino boards based on NINA wifi module.
+  Copyright (c) 2018 Arduino SA. All rights reserved.
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#ifndef wifistorage_h
+#define wifistorage_h
+
 #include "utility/wifi_drv.h"
 
 class WiFiStorageFile;
@@ -11,21 +33,21 @@ class WiFiStorageClass
 	static WiFiStorageFile open(String filename);
 
 	static bool exists(const char *filename) {
-		size_t len;
+		uint32_t len;
 		return (WiFiDrv::existsFile(filename, strlen(filename), &len) > 0);
 	}
-	static bool exists(const char *filename, size_t* len) {
+	static bool exists(const char *filename, uint32_t* len) {
 		return (WiFiDrv::existsFile(filename, strlen(filename), len) > 0);
 	}
 	static bool remove(const char *filename) {
 		WiFiDrv::deleteFile(filename, strlen(filename));
 		return true;
 	}
-	static bool read(const char *filename, size_t offset, uint8_t* buffer, size_t buffer_len) {
+	static bool read(const char *filename, uint32_t offset, uint8_t* buffer, uint32_t buffer_len) {
 		WiFiDrv::readFile(filename, strlen(filename), offset, buffer, buffer_len);
 		return true;
 	}
-	static bool write(const char *filename, size_t offset, uint8_t* buffer, size_t buffer_len) {
+	static bool write(const char *filename, uint32_t offset, uint8_t* buffer, uint32_t buffer_len) {
 		WiFiDrv::writeFile(filename, strlen(filename), offset, buffer, buffer_len);
 		return true;
 	}
@@ -37,10 +59,10 @@ class WiFiStorageClass
     static bool remove(String filename) {
     	return remove(filename.c_str());
 	}
-	static bool read(String filename, size_t offset, uint8_t* buffer, size_t buffer_len) {
+	static bool read(String filename, uint32_t offset, uint8_t* buffer, uint32_t buffer_len) {
 		return read(filename.c_str(), offset, buffer, buffer_len);
 	}
-	static bool write(String filename, size_t offset, uint8_t* buffer, size_t buffer_len) {
+	static bool write(String filename, uint32_t offset, uint8_t* buffer, uint32_t buffer_len) {
 		return write(filename.c_str(), offset, buffer, buffer_len);
 	}
     static bool download(String url, String filename) {
@@ -55,6 +77,7 @@ class WiFiStorageFile
 {
 public:
 	constexpr WiFiStorageFile(const char* _filename) : filename(_filename) { }
+
 	operator bool() {
 		return WiFiStorage.exists(filename, &length);
 	}
@@ -96,7 +119,9 @@ class WiFiStorageFile
 	}
 protected:
 	friend class WiFiStorageClass;
-	size_t offset = 0;
-	size_t length = 0;
+	uint32_t offset = 0;
+	uint32_t length = 0;
 	const char* filename;
 };
+
+#endif
\ No newline at end of file
diff --git a/src/utility/wifi_drv.cpp b/src/utility/wifi_drv.cpp
index 336076c7..de856e24 100644
--- a/src/utility/wifi_drv.cpp
+++ b/src/utility/wifi_drv.cpp
@@ -1110,7 +1110,7 @@ int8_t WiFiDrv::downloadFile(const char* url, uint8_t url_len, const char *filen
     return _data;
 }
 
-int8_t WiFiDrv::fileOperation(uint8_t operation, const char *filename, uint8_t filename_len, size_t offset, uint8_t* buffer, size_t len)
+int8_t WiFiDrv::fileOperation(uint8_t operation, const char *filename, uint8_t filename_len, uint32_t offset, uint8_t* buffer, uint32_t len)
 {
     WAIT_FOR_SLAVE_SELECT();
     // Send Command
diff --git a/src/utility/wifi_drv.h b/src/utility/wifi_drv.h
index f10af3c0..883b7e68 100644
--- a/src/utility/wifi_drv.h
+++ b/src/utility/wifi_drv.h
@@ -288,18 +288,18 @@ class WiFiDrv
 
     static int8_t downloadFile(const char* url, uint8_t url_len, const char *filename, uint8_t filename_len);
 
-    static int8_t fileOperation(uint8_t operation, const char *filename, uint8_t filename_len, size_t offset, uint8_t* buffer, size_t len);
+    static int8_t fileOperation(uint8_t operation, const char *filename, uint8_t filename_len, uint32_t offset, uint8_t* buffer, uint32_t len);
 
-    static int8_t readFile(const char *filename, uint8_t filename_len, size_t offset, uint8_t* buffer, size_t buffer_len) {
+    static int8_t readFile(const char *filename, uint8_t filename_len, uint32_t offset, uint8_t* buffer, uint32_t buffer_len) {
         return fileOperation(READ_FILE, filename, filename_len, offset, buffer, buffer_len);
     };
-    static int8_t writeFile(const char *filename, uint8_t filename_len, size_t offset, uint8_t* buffer, size_t buffer_len) {
+    static int8_t writeFile(const char *filename, uint8_t filename_len, uint32_t offset, uint8_t* buffer, uint32_t buffer_len) {
         return fileOperation(WRITE_FILE, filename, filename_len, offset, buffer, buffer_len);
     };
     static int8_t deleteFile(const char *filename, uint8_t filename_len)  {
         return fileOperation(DELETE_FILE, filename, filename_len, 0, NULL, 0);
     };
-    static int8_t existsFile(const char *filename, uint8_t filename_len, size_t* len)  {
+    static int8_t existsFile(const char *filename, uint8_t filename_len, uint32_t* len)  {
         int32_t length = 0;
         fileOperation(EXISTS_FILE, filename, filename_len, 0, (uint8_t*)&length, sizeof(length));
         *len = length;