Somehow I still missed one :-|

src/gps/NMEAWPL.cpp

@@ -19,7 +19,7 @@ uint32_t printWPL(char *buf, const Position &pos, const char *name)
 {
     uint32_t len = sprintf(buf, "$GNWPL,%07.2f,%c,%08.2f,%c,%s", pos.latitude_i * 1e-5, pos.latitude_i < 0 ? 'S' : 'N', pos.longitude_i * 1e-5, pos.longitude_i < 0 ? 'W' : 'E', name);
     uint32_t chk = 0;
-    for (uint i = 1; i < len; i++) {
+    for (uint32_t i = 1; i < len; i++) {
         chk ^= buf[i];
     }
     len += sprintf(buf + len, "*%02X\r\n", chk);