diff --git a/lib/Makefile b/lib/Makefile
index 5f583aed37d94c9a7cd54ef89a62795358fa6c99..2fd32798a081bd6245beb82d78369f947d792d01 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -19,7 +19,10 @@ obj-$(CONFIG_ARCH_AT91) += at91/
 obj-$(CONFIG_OPTEE) += optee/
 
 obj-$(CONFIG_AES) += aes.o
-obj-y += charset.o
+
+ifndef API_BUILD
+obj-$(CONFIG_EFI_LOADER) += charset.o
+endif
 obj-$(CONFIG_USB_TTY) += circbuf.o
 obj-y += crc7.o
 obj-y += crc8.o
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index ef8b0b5989573cde3c35e35dc29d81c56e16f880..632796f864df42a076ef532cbe19713e3555203b 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -274,6 +274,8 @@ static char *string(char *buf, char *end, char *s, int field_width,
 	return buf;
 }
 
+/* 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)
 {
@@ -294,8 +296,6 @@ static char *string16(char *buf, char *end, u16 *s, int field_width,
 	return buf;
 }
 
-/* Device paths only exist in the EFI context. */
-#if CONFIG_IS_ENABLED(EFI_LOADER) && !defined(API_BUILD)
 static char *device_path_string(char *buf, char *end, void *dp, int field_width,
 				int precision, int flags)
 {
@@ -612,10 +612,14 @@ repeat:
 			continue;
 
 		case 's':
-			if (qualifier == 'l' && !IS_ENABLED(CONFIG_SPL_BUILD)) {
+/* U-Boot uses UTF-16 strings in the EFI context only. */
+#if CONFIG_IS_ENABLED(EFI_LOADER) && !defined(API_BUILD)
+			if (qualifier == 'l') {
 				str = string16(str, end, va_arg(args, u16 *),
 					       field_width, precision, flags);
-			} else {
+			} else
+#endif
+			{
 				str = string(str, end, va_arg(args, char *),
 					     field_width, precision, flags);
 			}