diff --git a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.c b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.c
index 7d26c41ccc..7827b72be1 100644
--- a/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.c
+++ b/OvmfPkg/QemuFlashFvbServicesRuntimeDxe/FwBlockService.c
@@ -197,6 +197,7 @@ Returns:
 {
   EFI_FW_VOL_INSTANCE *FwhRecord;
 
+  *FwhInstance = NULL;
   if (Instance >= Global->NumFv) {
     return EFI_INVALID_PARAMETER;
   }