From 78b621264cc6b18bb721b2a583aff3e41e6dbd16 Mon Sep 17 00:00:00 2001
From: towelbyte <andrej@towelbyte.net>
Date: Fri, 26 Jun 2026 20:23:13 +0200
Subject: [PATCH] Fix (limit) 'lf cotag demod' custom clock argument

---
 client/src/cmdlfcotag.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/client/src/cmdlfcotag.c b/client/src/cmdlfcotag.c
index 9a1d154e9..2ffab3c54 100644
--- a/client/src/cmdlfcotag.c
+++ b/client/src/cmdlfcotag.c
@@ -428,6 +428,10 @@ end:
 
 int demodCOTAG(bool verbose, int clock, int threshold) {
     int clk = (clock > 0) ? clock : LF_COTAG_CLOCK;
+    if (clk < 32) {
+        PrintAndLogEx(FAILED, "custom clock must be >= 32, got " _RED_("%d"), clk);
+        return PM3_EINVARG;
+    }
     return demod_cotag(g_GraphBuffer, (int)g_GraphTraceLen, clk, -1, threshold, verbose);
 }