I don't understand why you are changing the vbios. Are you changing the intel cpu vbios or switching a nvidia 680 into an 880 bios. You cant swap Vbios like that. It is programmed for that particular chip architecture and memory. Its not physical, its a completely different programming.
Either way you shouldn't have to touch the Vbios at all.
Have you tried starting the laptop with the 880 in it and left it to run for a minute, hard restart, and try to boot again. The system uefi bios probably is still using the stored 680 bios and trying to boot from it. If the system fails to boot several times it will usually detect an error and then do a complete refresh of the system hardware detection and configuration. You can enable this in the system bios too, by switching the system to legacy boot (i forget the actual name) but I think it has CSM in it.
(The Compatibility Support Module (CSM) is a component of the UEFI firmware that provides legacy BIOS compatibility by emulating a BIOS)