diff --git a/src/avrdude/CMakeLists.txt b/src/avrdude/CMakeLists.txt
index 1022a5c0e..0e9b9e6d4 100644
--- a/src/avrdude/CMakeLists.txt
+++ b/src/avrdude/CMakeLists.txt
@@ -1,5 +1,7 @@
 cmake_minimum_required(VERSION 3.0)
 
+set(CMAKE_CXX_STANDARD 11)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
 add_definitions(-D_BSD_SOURCE -D_DEFAULT_SOURCE)   # To enable various useful macros and functions on Unices
 remove_definitions(-D_UNICODE -DUNICODE)
@@ -68,6 +70,7 @@ set(AVRDUDE_SOURCES
 )
 if (MSVC)
     set(AVRDUDE_SOURCES ${AVRDUDE_SOURCES}
+        windows/utf8.c
         windows/unistd.cpp
         windows/getopt.c
     )
@@ -90,7 +93,7 @@ add_custom_target(gen_conf_h
 add_library(avrdude STATIC ${AVRDUDE_SOURCES})
 add_dependencies(avrdude gen_conf_h)
 
-add_executable(avrdude-slic3r main-standalone.c)
+add_executable(avrdude-slic3r main-standalone.cpp)
 target_link_libraries(avrdude-slic3r avrdude)
 
 if (WIN32)
diff --git a/src/avrdude/fileio.c b/src/avrdude/fileio.c
index dcd0d6a66..7803497a0 100644
--- a/src/avrdude/fileio.c
+++ b/src/avrdude/fileio.c
@@ -40,6 +40,9 @@
 #include "avrdude.h"
 #include "libavrdude.h"
 
+#if defined(WIN32NATIVE)
+#include "windows/utf8.h"
+#endif
 
 #define IHEX_MAXDATA 256
 
@@ -110,7 +113,7 @@ FILE *fopen_utf8(const char *filename, const char *mode)
   static wchar_t mode_buffer[MAX_MODE_LEN];
 
   if (MultiByteToWideChar(CP_UTF8, 0, filename, -1, fname_buffer, PATH_MAX) == 0) { return NULL; }
-  if (MultiByteToWideChar(CP_ACP, 0, mode, -1, mode_buffer, MAX_MODE_LEN) == 0) { return NULL; }
+  if (MultiByteToWideChar(CP_UTF8, 0, mode, -1, mode_buffer, MAX_MODE_LEN) == 0) { return NULL; }
 
   return _wfopen(fname_buffer, mode_buffer);
 #else
diff --git a/src/avrdude/main-standalone.c b/src/avrdude/main-standalone.c
deleted file mode 100644
index 7cfc6f210..000000000
--- a/src/avrdude/main-standalone.c
+++ /dev/null
@@ -1,7 +0,0 @@
-#include "avrdude.h"
-
-
-int main(int argc, char *argv[])
-{
-	return avrdude_main(argc, argv);
-}
diff --git a/src/avrdude/main-standalone.cpp b/src/avrdude/main-standalone.cpp
new file mode 100644
index 000000000..df6d79e13
--- /dev/null
+++ b/src/avrdude/main-standalone.cpp
@@ -0,0 +1,54 @@
+extern "C" {
+#include "avrdude.h"
+}
+
+
+#ifdef WIN32
+#include <stdlib.h>
+#include <vector>
+
+extern "C" {
+#include "windows/utf8.h"
+}
+
+struct ArgvUtf8 : std::vector<char*>
+{
+	int argc;
+
+	ArgvUtf8(int argc_w, wchar_t *argv_w[]) : std::vector<char*>(argc_w + 1, nullptr), argc(0)
+	{
+		for (int i = 0; i < argc_w; i++) {
+			char *arg_utf8 = ::wstr_to_utf8(argv_w[i], -1);
+			if (arg_utf8 != nullptr) {
+				operator[](i) = arg_utf8;
+				argc = i + 1;
+			} else {
+				break;
+			}
+		}
+	}
+
+	~ArgvUtf8()
+	{
+		for (char *arg : *this) {
+			if (arg != nullptr) {
+				::free(arg);
+			}
+		}
+	}
+};
+
+int wmain(int argc_w, wchar_t *argv_w[])
+{
+	ArgvUtf8 argv_utf8(argc_w, argv_w);
+	return ::avrdude_main(argv_utf8.argc, &argv_utf8[0]);
+}
+
+#else
+
+int main(int argc, char *argv[])
+{
+	return ::avrdude_main(argc, argv);
+}
+
+#endif
diff --git a/src/avrdude/main.c b/src/avrdude/main.c
index 0f8807122..8f9040349 100644
--- a/src/avrdude/main.c
+++ b/src/avrdude/main.c
@@ -812,7 +812,6 @@ int avrdude_main(int argc, char * argv [])
 
   // rc = read_config(sys_config);
   rc = read_config_builtin();
-  avrdude_message(MSG_NOTICE, "\n\nread_config_builtin: %d\n\n", rc);
   if (rc) {
     // avrdude_message(MSG_INFO, "%s: error reading system wide configuration file \"%s\"\n",
     //                 progname, sys_config);
diff --git a/src/avrdude/ser_win32.c b/src/avrdude/ser_win32.c
index 4e1713128..c62e83608 100644
--- a/src/avrdude/ser_win32.c
+++ b/src/avrdude/ser_win32.c
@@ -34,16 +34,63 @@
 
 #include <windows.h>
 #include <stdio.h>
+#include <string.h>
 #include <ctype.h>   /* for isprint */
 #include <errno.h>   /* ENOTTY */
 
 #include "avrdude.h"
 #include "libavrdude.h"
+#include "windows/utf8.h"
 
 long serial_recv_timeout = 5000; /* ms */
 
 #define W32SERBUFSIZE 1024
 
+
+// Get last error message string in UTF-8
+// Always return a valid null-terminated string
+// The returned string should be freed by the caller
+char* last_error_string(int wsa)
+{
+	LPWSTR wbuffer = NULL;
+
+	(void)wsa;
+
+	DWORD wbuffer_len = FormatMessageW(
+		FORMAT_MESSAGE_ALLOCATE_BUFFER |
+		FORMAT_MESSAGE_FROM_SYSTEM |
+		FORMAT_MESSAGE_IGNORE_INSERTS,
+		NULL,
+#ifdef HAVE_LIBWS2_32
+		wsa ? WSAGetLastError() : GetLastError(),
+#else
+		GetLastError(),
+#endif
+		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
+		(LPWSTR)&wbuffer,
+		0,
+		NULL);
+
+	if (wbuffer_len == 0) {
+		return NULL;
+	}
+
+	char *res = wstr_to_utf8(wbuffer, wbuffer_len);
+
+	LocalFree(wbuffer);
+
+	if (res == NULL) {
+		// If we get here, conversion to UTF-8 failed
+		res = strdup("(could not get error message)");
+		if (res == NULL) {
+			avrdude_oom("last_error_string(): out of memory\n");
+		}
+	}
+
+	return res;
+}
+
+
 struct baud_mapping {
   long baud;
   DWORD speed;
@@ -129,7 +176,6 @@ static int
 net_open(const char *port, union filedescriptor *fdp)
 {
 	WSADATA wsaData;
-	LPVOID lpMsgBuf;
 
 	char *hstr, *pstr, *end;
 	unsigned int pnum;
@@ -175,18 +221,10 @@ net_open(const char *port, union filedescriptor *fdp)
 	free(hstr);
 
 	if ((fd = socket(PF_INET, SOCK_STREAM, 0)) < 0) {
-		FormatMessage(
-			FORMAT_MESSAGE_ALLOCATE_BUFFER |
-			FORMAT_MESSAGE_FROM_SYSTEM |
-			FORMAT_MESSAGE_IGNORE_INSERTS,
-			NULL,
-			WSAGetLastError(),
-			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-			(LPTSTR)&lpMsgBuf,
-			0,
-			NULL);
-		avrdude_message(MSG_INFO, "%s: net_open(): Cannot open socket: %s\n", progname, (char *)lpMsgBuf);
-		LocalFree(lpMsgBuf);
+		const char *error = last_error_string(1);
+		avrdude_message(MSG_INFO, "%s: net_open(): Cannot open socket: %s\n", progname, error);
+		free(error);
+
 		return -1;
 	}
 
@@ -196,18 +234,9 @@ net_open(const char *port, union filedescriptor *fdp)
 	memcpy(&(sockaddr.sin_addr.s_addr), hp->h_addr, sizeof(struct in_addr));
 
 	if (connect(fd, (struct sockaddr *)&sockaddr, sizeof(sockaddr))) {
-		FormatMessage(
-			FORMAT_MESSAGE_ALLOCATE_BUFFER |
-			FORMAT_MESSAGE_FROM_SYSTEM |
-			FORMAT_MESSAGE_IGNORE_INSERTS,
-			NULL,
-			WSAGetLastError(),
-			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-			(LPTSTR)&lpMsgBuf,
-			0,
-			NULL);
-		avrdude_message(MSG_INFO, "%s: net_open(): Connect failed: %s\n", progname, (char *)lpMsgBuf);
-		LocalFree(lpMsgBuf);
+		const char *error = last_error_string(1);
+		avrdude_message(MSG_INFO, "%s: net_open(): Connect failed: %s\n", progname);
+		free(error);
 		return -1;
 	}
 
@@ -221,7 +250,6 @@ net_open(const char *port, union filedescriptor *fdp)
 
 static int ser_open(char * port, union pinfo pinfo, union filedescriptor *fdp)
 {
-	LPVOID lpMsgBuf;
 	HANDLE hComPort=INVALID_HANDLE_VALUE;
 	char *newname = 0;
 
@@ -261,19 +289,9 @@ static int ser_open(char * port, union pinfo pinfo, union filedescriptor *fdp)
 		OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
 
 	if (hComPort == INVALID_HANDLE_VALUE) {
-		FormatMessage(
-			FORMAT_MESSAGE_ALLOCATE_BUFFER |
-			FORMAT_MESSAGE_FROM_SYSTEM |
-			FORMAT_MESSAGE_IGNORE_INSERTS,
-			NULL,
-			GetLastError(),
-			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
-			(LPTSTR) &lpMsgBuf,
-			0,
-			NULL);
-		avrdude_message(MSG_INFO, "%s: ser_open(): can't open device \"%s\": %s\n",
-				progname, port, (char*)lpMsgBuf);
-		LocalFree( lpMsgBuf );
+		const char *error = last_error_string(0);
+		avrdude_message(MSG_INFO, "%s: ser_open(): can't open device \"%s\": %s\n", progname, port, error);
+		free(error);
 		return -1;
 	}
 
@@ -346,14 +364,13 @@ static int ser_set_dtr_rts(union filedescriptor *fd, int is_on)
 #ifdef HAVE_LIBWS2_32
 static int net_send(union filedescriptor *fd, const unsigned char * buf, size_t buflen)
 {
-	LPVOID lpMsgBuf;
 	int rc;
 	const unsigned char *p = buf;
 	size_t len = buflen;
 
 	if (fd->ifd < 0) {
 		avrdude_message(MSG_NOTICE, "%s: net_send(): connection not open\n", progname);
-		exit(1);
+		return -1;
 	}
 
 	if (!len) {
@@ -382,19 +399,10 @@ static int net_send(union filedescriptor *fd, const unsigned char * buf, size_t
 	while (len) {
 		rc = send(fd->ifd, p, (len > 1024) ? 1024 : len, 0);
 		if (rc < 0) {
-			FormatMessage(
-				FORMAT_MESSAGE_ALLOCATE_BUFFER |
-				FORMAT_MESSAGE_FROM_SYSTEM |
-				FORMAT_MESSAGE_IGNORE_INSERTS,
-				NULL,
-				WSAGetLastError(),
-				MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-				(LPTSTR)&lpMsgBuf,
-				0,
-				NULL);
-			avrdude_message(MSG_INFO, "%s: net_send(): send error: %s\n", progname, (char *)lpMsgBuf);
-			LocalFree(lpMsgBuf);
-			exit(1);
+			const char *error = last_error_string(1);
+			avrdude_message(MSG_INFO, "%s: net_send(): send error: %s\n", progname, error);
+			free(error);
+			return -1;
 		}
 		p += rc;
 		len -= rc;
@@ -423,8 +431,7 @@ static int ser_send(union filedescriptor *fd, const unsigned char * buf, size_t
 	HANDLE hComPort=(HANDLE)fd->pfd;
 
 	if (hComPort == INVALID_HANDLE_VALUE) {
-		avrdude_message(MSG_INFO, "%s: ser_send(): port not open\n",
-              progname); 
+		avrdude_message(MSG_INFO, "%s: ser_send(): port not open\n", progname);
 		return -1;
 	}
 
@@ -449,18 +456,18 @@ static int ser_send(union filedescriptor *fd, const unsigned char * buf, size_t
 		}
       avrdude_message(MSG_INFO, "\n");
 	}
-	
+
 	serial_w32SetTimeOut(hComPort,500);
 
-	if (!WriteFile (hComPort, buf, buflen, &written, NULL)) {
-		avrdude_message(MSG_INFO, "%s: ser_send(): write error: %s\n",
-              progname, "sorry no info avail"); // TODO
+	if (!WriteFile(hComPort, buf, buflen, &written, NULL)) {
+		const char *error = last_error_string(0);
+		avrdude_message(MSG_INFO, "%s: ser_send(): write error: %s\n", progname, error);
+		free(error);
 		return -1;
 	}
 
 	if (written != buflen) {
-		avrdude_message(MSG_INFO, "%s: ser_send(): size/send mismatch\n",
-              progname); 
+		avrdude_message(MSG_INFO, "%s: ser_send(): size/send mismatch\n", progname);
 		return -1;
 	}
 
@@ -471,7 +478,6 @@ static int ser_send(union filedescriptor *fd, const unsigned char * buf, size_t
 #ifdef HAVE_LIBWS2_32
 static int net_recv(union filedescriptor *fd, unsigned char * buf, size_t buflen)
 {
-	LPVOID lpMsgBuf;
 	struct timeval timeout, to2;
 	fd_set rfds;
 	int nfds;
@@ -481,7 +487,7 @@ static int net_recv(union filedescriptor *fd, unsigned char * buf, size_t buflen
 
 	if (fd->ifd < 0) {
 		avrdude_message(MSG_INFO, "%s: net_recv(): connection not open\n", progname);
-		exit(1);
+		return -1;
 	}
 
 	timeout.tv_sec  = serial_recv_timeout / 1000L;
@@ -504,37 +510,19 @@ reselect:
 				avrdude_message(MSG_NOTICE, "%s: ser_recv(): programmer is not responding, reselecting\n", progname);
 				goto reselect;
 			} else {
-				FormatMessage(
-					FORMAT_MESSAGE_ALLOCATE_BUFFER |
-					FORMAT_MESSAGE_FROM_SYSTEM |
-					FORMAT_MESSAGE_IGNORE_INSERTS,
-					NULL,
-					WSAGetLastError(),
-					MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-					(LPTSTR)&lpMsgBuf,
-					0,
-					NULL);
-				avrdude_message(MSG_INFO, "%s: ser_recv(): select(): %s\n", progname, (char *)lpMsgBuf);
-				LocalFree(lpMsgBuf);
-				exit(1);
+				const char *error = last_error_string(1);
+				avrdude_message(MSG_INFO, "%s: ser_recv(): select(): %s\n", progname, error);
+				free(error);
+				return -1;
 			}
 		}
 
 		rc = recv(fd->ifd, p, (buflen - len > 1024) ? 1024 : buflen - len, 0);
 		if (rc < 0) {
-			FormatMessage(
-				FORMAT_MESSAGE_ALLOCATE_BUFFER |
-				FORMAT_MESSAGE_FROM_SYSTEM |
-				FORMAT_MESSAGE_IGNORE_INSERTS,
-				NULL,
-				WSAGetLastError(),
-				MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
-				(LPTSTR)&lpMsgBuf,
-				0,
-				NULL);
-			avrdude_message(MSG_INFO, "%s: ser_recv(): read error: %s\n", progname, (char *)lpMsgBuf);
-			LocalFree(lpMsgBuf);
-			exit(1);
+			const char *error = last_error_string(1);
+			avrdude_message(MSG_INFO, "%s: ser_recv(): read error: %s\n", progname, error);
+			free(error);
+			return -1;
 		}
 		p += rc;
 		len += rc;
@@ -579,37 +567,24 @@ static int ser_recv(union filedescriptor *fd, unsigned char * buf, size_t buflen
 	RETURN_IF_CANCEL();
 
 	HANDLE hComPort=(HANDLE)fd->pfd;
-	
+
 	if (hComPort == INVALID_HANDLE_VALUE) {
-		avrdude_message(MSG_INFO, "%s: ser_read(): port not open\n",
-              progname); 
+		avrdude_message(MSG_INFO, "%s: ser_read(): port not open\n", progname);
 		return -1;
 	}
-	
+
 	serial_w32SetTimeOut(hComPort, serial_recv_timeout);
-	
+
 	if (!ReadFile(hComPort, buf, buflen, &read, NULL)) {
-		LPVOID lpMsgBuf;
-		FormatMessage( 
-			FORMAT_MESSAGE_ALLOCATE_BUFFER | 
-			FORMAT_MESSAGE_FROM_SYSTEM | 
-			FORMAT_MESSAGE_IGNORE_INSERTS,
-			NULL,
-			GetLastError(),
-			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
-			(LPTSTR) &lpMsgBuf,
-			0,
-			NULL 	);
-		avrdude_message(MSG_INFO, "%s: ser_recv(): read error: %s\n",
-			      progname, (char*)lpMsgBuf);
-		LocalFree( lpMsgBuf );
+		const char *error = last_error_string(0);
+		avrdude_message(MSG_INFO, "%s: ser_recv(): read error: %s\n", progname, error);
+		free(error);
 		return -1;
 	}
 
 	/* time out detected */
 	if (read == 0) {
-		avrdude_message(MSG_NOTICE2, "%s: ser_recv(): programmer is not responding\n",
-                                progname);
+		avrdude_message(MSG_NOTICE2, "%s: ser_recv(): programmer is not responding\n", progname);
 		return -1;
 	}
 
@@ -664,20 +639,9 @@ static int ser_drain(union filedescriptor *fd, int display)
 
 		readres=ReadFile(hComPort, buf, 1, &read, NULL);
 		if (!readres) {
-			LPVOID lpMsgBuf;
-			FormatMessage( 
-				FORMAT_MESSAGE_ALLOCATE_BUFFER | 
-				FORMAT_MESSAGE_FROM_SYSTEM | 
-				FORMAT_MESSAGE_IGNORE_INSERTS,
-				NULL,
-				GetLastError(),
-				MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
-				(LPTSTR) &lpMsgBuf,
-				0,
-				NULL 	);
-			avrdude_message(MSG_INFO, "%s: ser_drain(): read error: %s\n",
-					  progname, (char*)lpMsgBuf);
-			LocalFree( lpMsgBuf );
+			const char *error = last_error_string(0);
+			avrdude_message(MSG_INFO, "%s: ser_drain(): read error: %s\n", progname, error);
+			free(error);
 			return -1;
 		}
 
diff --git a/src/avrdude/windows/utf8.c b/src/avrdude/windows/utf8.c
new file mode 100644
index 000000000..d3c51e67f
--- /dev/null
+++ b/src/avrdude/windows/utf8.c
@@ -0,0 +1,45 @@
+#include "utf8.h"
+
+
+char* wstr_to_utf8(LPWSTR wstr, int len)
+{
+	char *res = NULL;
+
+	int res_size = WideCharToMultiByte(CP_UTF8, 0, wstr, len, NULL, 0, NULL, NULL);
+	if (res_size > 0) {
+		// Note: WideCharToMultiByte doesn't null-terminate if real (ie. > 0) buffer length is passed
+		res = malloc(len != - 1 ? res_size + 1 : res_size);
+		if (res == NULL) { return NULL; }
+
+		if (WideCharToMultiByte(CP_UTF8, 0, wstr, len, res, res_size, NULL, NULL) == res_size) {
+			if (len != -1) { res[res_size] = '\0'; }
+		} else {
+			free(res);
+			return NULL;
+		}
+	}
+
+	return res;
+}
+
+LPWSTR utf8_to_wstr(const char *str, int len)
+{
+	LPWSTR res = NULL;
+
+	int res_size = MultiByteToWideChar(CP_UTF8, 0, str, len, NULL, 0);
+	if (res_size > 0) {
+		// Note: MultiByteToWideChar doesn't null-terminate if real (ie. > 0) buffer length is passed
+		res = malloc(len != - 1 ? res_size + 1 : res_size);
+
+		if (res == NULL) { return NULL; }
+
+		if (MultiByteToWideChar(CP_UTF8, 0, str, len, res, res_size) == res_size) {
+			if (len != -1) { res[res_size] = L'\0'; }
+		} else {
+			free(res);
+			return NULL;
+		}
+	}
+
+	return res;
+}
diff --git a/src/avrdude/windows/utf8.h b/src/avrdude/windows/utf8.h
new file mode 100644
index 000000000..a99fcbb7e
--- /dev/null
+++ b/src/avrdude/windows/utf8.h
@@ -0,0 +1,10 @@
+#ifndef SLIC3R_AVRDUDE_UTF8_H
+#define SLIC3R_AVRDUDE_UTF8_H
+
+#include <windows.h>
+
+extern char* wstr_to_utf8(LPWSTR wstr, int len);
+extern LPWSTR utf8_to_wstr(const char *str, int len);
+
+
+#endif  // SLIC3R_AVRDUDE_UTF8_H