diff --git a/lib/vtxprintf.c b/lib/vtxprintf.c
index 8a95ca1ec4..eb753f2975 100644
--- a/lib/vtxprintf.c
+++ b/lib/vtxprintf.c
@@ -202,7 +202,7 @@ int vtxprintf(void (*tx_byte)(unsigned char byte, void *arg), void *arg, const c
 			len = strnlen(s, precision);
 
 			for (i = 0; i < len; ++i)
-				if (!isprint(*s[i])) {
+				if (!isprint(s[i])) {
 					s = "<non-ASCII characters>";
 					len = strlen(s);
 					break;