diff --git a/ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c b/ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c
index 2dc9287020..4bb21aae6f 100644
--- a/ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c
+++ b/ShellPkg/Library/UefiShellTftpCommandLib/Tftp.c
@@ -197,6 +197,7 @@ DownloadFile (
 **/
 STATIC 
 EFI_STATUS 
+EFIAPI
 CheckPacket (
   IN EFI_MTFTP4_PROTOCOL  *This,
   IN EFI_MTFTP4_TOKEN     *Token,
@@ -940,6 +941,7 @@ Error :
 **/
 STATIC
 EFI_STATUS
+EFIAPI
 CheckPacket (
   IN EFI_MTFTP4_PROTOCOL  *This,
   IN EFI_MTFTP4_TOKEN     *Token,