diff --git a/Cryptlib/Include/openssl/err.h b/Cryptlib/Include/openssl/err.h
index bbfdb95..da589f8 100644
--- a/Cryptlib/Include/openssl/err.h
+++ b/Cryptlib/Include/openssl/err.h
@@ -352,7 +352,11 @@ void EFIAPI ERR_add_error_data(int num, ...);
 void ERR_add_error_data(int num, ...);
 #endif
 
+#if defined(OPENSSL_SYS_UEFI)
+void EFIAPI ERR_add_error_vdata(int num, va_list args);
+#else
 void ERR_add_error_vdata(int num, va_list args);
+#endif
 void ERR_load_strings(int lib, ERR_STRING_DATA str[]);
 void ERR_unload_strings(int lib, ERR_STRING_DATA str[]);
 void ERR_load_ERR_strings(void);
diff --git a/Cryptlib/OpenSSL/crypto/err/err.c b/Cryptlib/OpenSSL/crypto/err/err.c
index f98cce6..108b83a 100644
--- a/Cryptlib/OpenSSL/crypto/err/err.c
+++ b/Cryptlib/OpenSSL/crypto/err/err.c
@@ -1085,7 +1085,11 @@ void ERR_add_error_data(int num, ...)
     va_end(args);
 }
 
+#if defined(OPENSSL_SYS_UEFI)
+void EFIAPI ERR_add_error_vdata(int num, va_list args)
+#else
 void ERR_add_error_vdata(int num, va_list args)
+#endif
 {
     int i, n, s;
     char *str, *p, *a;