diff --git a/lib/libc/locale/ascii.c b/lib/libc/locale/ascii.c
index 784814d2664d..a70d71a7b88c 100644
--- a/lib/libc/locale/ascii.c
+++ b/lib/libc/locale/ascii.c
@@ -143,6 +143,7 @@ _ascii_mbsnrtowcs(wchar_t * __restrict dst, const char ** __restrict src,
 	nchr = 0;
 	while (len-- > 0 && nms-- > 0) {
 		if (*s & 0x80) {
+			*src = s;
 			errno = EILSEQ;
 			return ((size_t)-1);
 		}
@@ -177,6 +178,7 @@ _ascii_wcsnrtombs(char * __restrict dst, const wchar_t ** __restrict src,
 	nchr = 0;
 	while (len-- > 0 && nwc-- > 0) {
 		if (*s < 0 || *s > 127) {
+			*src = s;
 			errno = EILSEQ;
 			return ((size_t)-1);
 		}
diff --git a/lib/libc/locale/none.c b/lib/libc/locale/none.c
index c4695fd1222a..4e5a61d99540 100644
--- a/lib/libc/locale/none.c
+++ b/lib/libc/locale/none.c
@@ -174,6 +174,7 @@ _none_wcsnrtombs(char * __restrict dst, const wchar_t ** __restrict src,
 	nchr = 0;
 	while (len-- > 0 && nwc-- > 0) {
 		if (*s < 0 || *s > UCHAR_MAX) {
+			*src = s;
 			errno = EILSEQ;
 			return ((size_t)-1);
 		}