diff --git a/lib/Kconfig b/lib/Kconfig
index 10ba086..1883ac7 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -52,7 +52,7 @@
 
 config CHARSET
 	bool
-	default y if UT_UNICODE || EFI_LOADER || UFS
+	default y if UT_UNICODE || EFI_LOADER || UFS || EFI_APP
 	help
 	  Enables support for various conversions between different
 	  character sets, such as between unicode representations and
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index e634bd7..de9f236 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -276,9 +276,8 @@
 }
 
 /* U-Boot uses UTF-16 strings in the EFI context only. */
-#if CONFIG_IS_ENABLED(EFI_LOADER) && !defined(API_BUILD)
-static char *string16(char *buf, char *end, u16 *s, int field_width,
-		int precision, int flags)
+static __maybe_unused char *string16(char *buf, char *end, u16 *s,
+				     int field_width, int precision, int flags)
 {
 	const u16 *str = s ? s : L"<NULL>";
 	ssize_t i, len = utf16_strnlen(str, precision);
@@ -317,7 +316,6 @@
 	return buf;
 }
 #endif
-#endif
 
 static char *mac_address_string(char *buf, char *end, u8 *addr, int field_width,
 				int precision, int flags)
@@ -616,7 +614,8 @@
 
 		case 's':
 /* U-Boot uses UTF-16 strings in the EFI context only. */
-#if CONFIG_IS_ENABLED(EFI_LOADER) && !defined(API_BUILD)
+#if (CONFIG_IS_ENABLED(EFI_LOADER) || CONFIG_IS_ENABLED(EFI_APP)) && \
+	!defined(API_BUILD)
 			if (qualifier == 'l') {
 				str = string16(str, end, va_arg(args, u16 *),
 					       field_width, precision, flags);