diff --git a/libusb/os/windows_winusb.c b/libusb/os/windows_winusb.c
index 6c0db2a..ab49975 100644
--- a/libusb/os/windows_winusb.c
+++ b/libusb/os/windows_winusb.c
@@ -3234,7 +3234,11 @@
 
 	if (transfer->type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS) {
 		struct winusb_device_priv *priv = usbi_get_device_priv(transfer->dev_handle->dev);
-		CHECK_WINUSBX_AVAILABLE(sub_api);
+
+		if (sub_api == SUB_API_NOTSET)
+			sub_api = priv->sub_api;
+		if (WinUSBX[sub_api].hDll == NULL)
+			return LIBUSB_TRANSFER_ERROR;
 
 		// for isochronous, need to copy the individual iso packet actual_lengths and statuses
 		if ((sub_api == SUB_API_LIBUSBK) || (sub_api == SUB_API_LIBUSB0)) {
diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 1de3b3b..ae65857 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11718
+#define LIBUSB_NANO 11719