diff --git a/Library/OcBootManagementLib/OcBootManagementLib.c b/Library/OcBootManagementLib/OcBootManagementLib.c
index fe59ffcd..4b1555c7 100644
--- a/Library/OcBootManagementLib/OcBootManagementLib.c
+++ b/Library/OcBootManagementLib/OcBootManagementLib.c
@@ -49,6 +49,7 @@
 #include <Library/UefiLib.h>
 
 EFI_STATUS
+EFIAPI
 OcShowSimpleBootMenu (
   IN  OC_PICKER_CONTEXT           *Context,
   IN  OC_BOOT_ENTRY               *BootEntries,