Re: "To improve system performance, Lenovo is ... adopting RAID on the SSDs..."
> It's a laptop with ONE DRIVE BAY.
Are you sure it has a drive BAY at all? My Acer ultrabook (granted, it's from 2013 or so) has a 128GB SSD in it. Except it doesn't; it has 2x 64GB SSDs in it. I assume they're soldered onto the motherboard somehow.
With RAID enabled in the BIOS, Windows casually treats it as a single volume and you'd never know. To use Linux on it, you need to enable AHCI (which it *does* allow, unlike -- allegedly -- these Lenovo machines), at which point you need to monkey around with software RAID to get back to a single volume.