--- a/src/server/daemon/websocket.c	Sun Sep 25 09:33:39 2022 +0200
+++ b/src/server/daemon/websocket.c	Sun Sep 25 10:36:28 2022 +0200
@@ -304,7 +304,7 @@
 
 NSAPI_PUBLIC int websocket_send_text(SYS_NETFD csd, char *msg, size_t len) {
     char frame[WS_FRAMEHEADER_BUFLEN];
-    frame[0] = 129; // 0b10000001
+    frame[0] = (char)129; // 0b10000001
     size_t hlen;
     if(len < 126) {
         frame[1] = (char)len;