While BootMenuApp build in UEFI payload, PcdBootManagerMenuFile used to get Uiapp file guid used in BootMenuApp will same with Universal payload pkg, platform can not override it. we should add PlatformBootManagerLib for BootManagerMenuApp.inf in Edk2\UefiPayloadPkg\UefiPayloadPkg.dsc,after that we can override UiappGuid by platform side.