diff --git a/os/hal/ports/simulator/win32/hal_serial_lld.c b/os/hal/ports/simulator/win32/hal_serial_lld.c
index fcd4ab7f3..0bd8b4798 100644
--- a/os/hal/ports/simulator/win32/hal_serial_lld.c
+++ b/os/hal/ports/simulator/win32/hal_serial_lld.c
@@ -215,7 +215,7 @@ void sd_lld_init(void) {
   SD1.com_name = "SD1";
 #endif
 
-#if USE_WIN32_SERIAL1
+#if USE_WIN32_SERIAL2
   sdObjectInit(&SD2, NULL, NULL);
   SD2.com_listen = INVALID_SOCKET;
   SD2.com_data = INVALID_SOCKET;
@@ -241,7 +241,7 @@ void sd_lld_start(SerialDriver *sdp, const SerialConfig *config) {
     init(&SD1, SD1_PORT);
 #endif
 
-#if USE_WIN32_SERIAL1
+#if USE_WIN32_SERIAL2
   if (sdp == &SD2)
     init(&SD2, SD2_PORT);
 #endif
diff --git a/readme.txt b/readme.txt
index e00c28b66..2cf8443ee 100644
--- a/readme.txt
+++ b/readme.txt
@@ -123,6 +123,8 @@
 - RT:  Merged RT4.
 - NIL: Merged NIL2.
 - NIL: Added STM32F7 demo.
+- HAL: Fixed wrong check in win32 simulator serial driver (bug #765)
+       (backported to 16.1.6, 3.0.6, 2.6.10).
 - HAL: Fixed dependency on RT in hal_usb.c (bug #764)(backported to 16.1.6).
 - HAL: Fixed wrong backup domain reset in STM32L4xx\hal_lld (bug #763)
        (backported to 16.1.6).