diff --git a/include/charset.h b/include/charset.h
index 348bad5883a..2d1964287d8 100644
--- a/include/charset.h
+++ b/include/charset.h
@@ -303,6 +303,26 @@ size_t u16_strlcat(u16 *dest, const u16 *src, size_t count);
  */
 uint8_t *utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size);
 
+enum utf16_endian;
+
+/**
+ * utf16s_to_utf8s() - convert a UTF-16 string to UTF-8 with explicit endianness
+ *
+ * Linux NLS-compatible interface that wraps utf16_to_utf8(). Converts at
+ * most @inlen UTF-16 code units from @pwcs to UTF-8, stopping at a null
+ * character or when @maxout bytes have been written. Surrogate pairs are
+ * handled by the underlying utf16_to_utf8() implementation.
+ *
+ * @pwcs:	source UTF-16 string
+ * @inlen:	number of UTF-16 code units to convert
+ * @endian:	byte order of the source string (UTF16_BIG_ENDIAN, etc.)
+ * @s:		destination buffer for UTF-8 output
+ * @maxout:	size of the destination buffer in bytes
+ * Return:	number of bytes written to @s
+ */
+int utf16s_to_utf8s(const u16 *pwcs, int inlen, enum utf16_endian endian,
+		    u8 *s, int maxout);
+
 /**
  * utf_to_cp() - translate Unicode code point to 8bit codepage
  *
diff --git a/include/linux/nls.h b/include/linux/nls.h
new file mode 100644
index 00000000000..939dc1afaaa
--- /dev/null
+++ b/include/linux/nls.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Minimal NLS (National Language Support) stubs for U-Boot
+ *
+ * Based on the interface from Linux's include/linux/nls.h but heavily
+ * simplified: struct nls_table is trimmed to the fields used by isofs,
+ * load_nls() and unload_nls() are no-ops, and utf16s_to_utf8s() is a
+ * implementation wrapping utf16_to_utf8() in lib/charset.c
+ *
+ * Joliet support requires NLS for character set conversion. These stubs
+ * allow the code to compile without full NLS infrastructure.
+ */
+#ifndef _LINUX_NLS_H
+#define _LINUX_NLS_H
+
+#include <linux/types.h>
+
+#define NLS_MAX_CHARSET_SIZE	6
+
+/* UTF-16 byte order */
+enum utf16_endian {
+	UTF16_HOST_ENDIAN,
+	UTF16_LITTLE_ENDIAN,
+	UTF16_BIG_ENDIAN,
+};
+
+struct nls_table {
+	const char *charset;
+	int (*uni2char)(wchar_t uni, unsigned char *out, int boundlen);
+	int (*char2uni)(const unsigned char *rawstring, int boundlen,
+			wchar_t *uni);
+};
+
+static inline struct nls_table *load_nls(const char *charset)
+{
+	return NULL;
+}
+
+static inline struct nls_table *load_nls_default(void)
+{
+	return NULL;
+}
+
+static inline void unload_nls(struct nls_table *nls)
+{
+}
+
+#include <charset.h>
+
+#endif /* _LINUX_NLS_H */
diff --git a/lib/charset.c b/lib/charset.c
index 182c92a50c4..911659199d7 100644
--- a/lib/charset.c
+++ b/lib/charset.c
@@ -10,6 +10,7 @@
 #include <cp437.h>
 #include <efi_loader.h>
 #include <errno.h>
+#include <linux/nls.h>
 #include <malloc.h>
 
 /**
@@ -311,6 +312,34 @@ int utf16_utf8_strncpy(char **dst, const u16 *src, size_t count)
 	return 0;
 }
 
+int utf16s_to_utf8s(const u16 *pwcs, int inlen, enum utf16_endian endian,
+		    u8 *s, int maxout)
+{
+	u16 *tmp;
+	u8 *start = s;
+	int i;
+
+	tmp = malloc(inlen * sizeof(u16));
+	if (!tmp)
+		return 0;
+
+	for (i = 0; i < inlen; i++) {
+		if (endian == UTF16_BIG_ENDIAN)
+			tmp[i] = __be16_to_cpu(pwcs[i]);
+		else
+			tmp[i] = __le16_to_cpu(pwcs[i]);
+		if (!tmp[i]) {
+			inlen = i;
+			break;
+		}
+	}
+
+	s = utf16_to_utf8(s, tmp, inlen);
+	free(tmp);
+
+	return min((int)(s - start), maxout);
+}
+
 s32 utf_to_lower(const s32 code)
 {
 	struct capitalization_table *pos = capitalization_table;