diff -r 3ee337c8c769 -r 2670f5c53caf svghmi/svghmi.js
--- a/svghmi/svghmi.js	Sat Apr 04 22:32:54 2020 +0200
+++ b/svghmi/svghmi.js	Tue Apr 07 10:01:23 2020 +0200
@@ -236,7 +236,8 @@
         new Uint32Array([index]),
         tobinary(value)]);
 
-    cache[index] = value;
+    // DON'T DO THAT unless read_iterator in svghmi.c modifies wbuf as well, not only rbuf
+    // cache[index] = value;
 };
 
 function apply_hmi_value(index, new_val) {