diff --git a/tools/Makefile b/tools/Makefile
index ebdff78..26affcd 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -2,6 +2,7 @@ CFLAGS ?= -W -Wall -Wextra -Werror -Wundef -Wshadow -Wdouble-promotion -Os
 BINDIR ?= .
 CWD ?= $(realpath $(CURDIR))
 DOCKER = docker run $(DA) --rm -e WINEDEBUG=-all -v $(CWD):$(CWD) -w $(CWD)
+SERIAL_PORT ?= /dev/ttyUSB0
 
 all:
 	@echo available targets: slipterm esputil test examples
@@ -11,8 +12,12 @@ esputil: esputil.c
 
 esputil.exe: esputil.c
 	$(DOCKER) mdashnet/vc98 wine cl /nologo /W3 /Os $? /Fe$@
-	$(DOCKER) mdashnet/vc98 wine $@ -v -p COM33 info
-#	$(DOCKER) mdashnet/mingw i686-w64-mingw32-gcc $(CFLAGS) $? -o $@
+
+test_esputil_windows: esputil.exe
+	ln -fs $(SERIAL_PORT) ~/.wine/dosdevices/com55 && wine $? -p '\\.\COM55' -v info
+#	$(DOCKER) -it --device $(SERIAL_PORT) mdashnet/vc98 \
+    ln -fs $(SERIAL_PORT) /root/.wine/dosdevices/com3 ; \
+    wine $@ -v -p '\\.\COM3' monitor
 
 slipterm: slipterm.c
 	$(CC) $(CFLAGS) $? -lpcap -lutil -o $(BINDIR)/$@
diff --git a/tools/esputil.c b/tools/esputil.c
index d6968f2..403c4ad 100644
--- a/tools/esputil.c
+++ b/tools/esputil.c
@@ -187,35 +187,60 @@ static uint8_t checksum(const uint8_t *buf, size_t len) {
   return checksum2(0xef, buf, len);
 }
 
-#ifdef _WIN32
+#ifdef _WIN32  // Windows - specific routines
 static void sleep_ms(int milliseconds) {
   Sleep(milliseconds);
 }
 
 static void flushio(int fd) {
-  (void) fd;
+  PurgeComm((HANDLE) _get_osfhandle(fd), PURGE_RXCLEAR | PURGE_TXCLEAR);
 }
 
-static int open_serial(const char *name, int baud, bool verbose) {
-  int fd = open(name, O_RDWR);
-  if (fd < 0) fail("open(%s): %d (%s)\n", name, fd, strerror(errno));
-  return fd;
+static void change_baud(int fd, int baud, bool verbose) {
+  DCB cfg = {sizeof(cfg)};
+  HANDLE h = (HANDLE) _get_osfhandle(fd);
+  if (GetCommState(h, &cfg)) {
+    cfg.ByteSize = 8;
+    cfg.Parity = NOPARITY;
+    cfg.StopBits = ONESTOPBIT;
+    cfg.fBinary = TRUE;
+    cfg.fParity = TRUE;
+    cfg.BaudRate = baud;
+    SetCommState(h, &cfg);
+  } else {
+    fail("GetCommState(%x): %d\n", h, GetLastError());
+  }
 }
 
-static void change_baud(int fd, int baud, bool verbose) {
+static int open_serial(const char *name, int baud, bool verbose) {
+  COMMTIMEOUTS ct = {1, 0, 1, 0, MAXDWORD};  // 1 ms read timeout
+  int fd = open(name, O_RDWR | O_BINARY);
+  if (fd < 0) fail("open(%s): %s\n", name, strerror(errno));
+  change_baud(fd, baud, verbose);
+  SetCommTimeouts((HANDLE) _get_osfhandle(fd), &ct);
+  return fd;
 }
 
 static int iowait(int fd, int ms) {
-  return 0;
+  COMSTAT cs = {0};
+  DWORD errors, flags = 0;
+  int i;
+  for (i = 0; i < ms && flags == 0; i++) {
+    sleep_ms(1);
+    ClearCommError((HANDLE) _get_osfhandle(fd), &errors, &cs);
+    if (cs.cbInQue > 0) flags |= 2;  // There is something to read
+  }
+  return flags;
 }
 
 static void set_rts(int fd, bool value) {
+  EscapeCommFunction((HANDLE) _get_osfhandle(fd), value ? SETRTS : CLRRTS);
 }
 
 static void set_dtr(int fd, bool value) {
+  EscapeCommFunction((HANDLE) _get_osfhandle(fd), value ? SETDTR : CLRDTR);
 }
-
-#else
+#else   // UNIX - specific routines
 static void set_rts(int fd, bool value) {
   int v = TIOCM_RTS;
   ioctl(fd, value ? TIOCMBIS : TIOCMBIC, &v);
@@ -305,7 +330,7 @@ static int iowait(int fd, int ms) {
   if (FD_ISSET(fd, &rset)) ready |= 2;
   return ready;
 }
-#endif
+#endif  // End of UNIX-specific routines
 
 static void hard_reset(int fd) {
   set_dtr(fd, false);  // IO0 -> HIGH