diff --git a/frontend/index.html b/frontend/index.html
index 7124798..81b2a26 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -14019,6 +14019,9 @@ function efArrSc(tlv) {
 	if (tag === 0x97) return 'never';
 	if (tag === 0x9E) return 'security condition 0x' + efHex(v);
 	if (tag === 0xA4) {
+		// An AT control reference template carries one key reference and one
+		// usage qualifier (ISO 7816-4 6.3.1); if a malformed CRT repeats the
+		// '83' tag, the last one wins here.
 		let ref = null, uq = null;
 		for (const t of efTlv(v)) {
 			if (t.tag === 0x83 && t.value.length) ref = t.value[0];
diff --git a/frontend/sw.js b/frontend/sw.js
index 445f2a2..cfac815 100644
--- a/frontend/sw.js
+++ b/frontend/sw.js
@@ -1,4 +1,4 @@
-const CACHE = 'simple-v256';
+const CACHE = 'simple-v257';
 const URLS = [
   'index.html',
   'help.html',