diff --git a/client/cmdhfthinfilm.c b/client/cmdhfthinfilm.c
index 38595f3f5..336843b92 100644
--- a/client/cmdhfthinfilm.c
+++ b/client/cmdhfthinfilm.c
@@ -73,7 +73,7 @@ static int print_barcode(uint8_t *barcode, const size_t barcode_len) {
     for (uint8_t i = 0; i < strlen(s); i++) {
 
         // terminate string
-        if (s[i] == 0xFE) {
+        if ((uint8_t) s[i] == 0xFE) {
             s[i] = 0;
             break;
         }