diff --git a/MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleLib.c b/MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleLib.c
index 36efd64c4c..8befbae1de 100644
--- a/MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleLib.c
+++ b/MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleLib.c
@@ -49,7 +49,7 @@ EFI_EVENT  mDxeCapsuleLibEndOfDxeEvent = NULL;
 
 EDKII_FIRMWARE_MANAGEMENT_PROGRESS_PROTOCOL  *mFmpProgress = NULL;
 
-extern BOOLEAN  mDxeCapsuleLibReadyToBootEvent;
+BOOLEAN  mDxeCapsuleLibReadyToBootEvent = FALSE;
 
 /**
   Initialize capsule related variables.
diff --git a/MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleRuntime.c b/MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleRuntime.c
index efff714d01..855b7a60fc 100644
--- a/MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleRuntime.c
+++ b/MdeModulePkg/Library/DxeCapsuleLibFmp/DxeCapsuleRuntime.c
@@ -24,7 +24,7 @@
 extern EFI_SYSTEM_RESOURCE_TABLE  *mEsrtTable;
 EFI_EVENT                         mDxeRuntimeCapsuleLibVirtualAddressChangeEvent = NULL;
 EFI_EVENT                         mDxeRuntimeCapsuleLibReadyToBootEvent          = NULL;
-BOOLEAN                           mDxeCapsuleLibReadyToBootEvent                 = FALSE;
+extern BOOLEAN                    mDxeCapsuleLibReadyToBootEvent;
 
 /**
   Convert EsrtTable physical address to virtual address.