diff --git a/client/src/cmdlf.c b/client/src/cmdlf.c
index c324a7ba9..f7ffab795 100644
--- a/client/src/cmdlf.c
+++ b/client/src/cmdlf.c
@@ -324,7 +324,7 @@ int CmdLFCommandRead(const char *Cmd) {
     uint32_t samples = 0;
     uint16_t datalen = 0;
 
-    uint8_t payload_header_size = 12;
+    const uint8_t payload_header_size = 12;
     struct p {
         uint32_t delay;
         uint16_t ones;