mSATA SSD not visible from dom0

I just installed an mSATA SSD in my modified ThinkPad x230: I have what’s called an x330 (X230 (X330) – XY Tech), which is an x230 with an additional mSATA under the palm rest by soldering an adapter board onto the motherboard.

However, when I put my machine back together and booted Qubes, there was an error message that showed up on the boot screen pretty much continually while I entered my passphrase to unlock my hard disk:

"ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 318)"

I did double-check that the SSD was well-seated in the mSATA adaptor. In dom0, I only see /dev/sda, without a second drive showing up.

I’m not a hardware hacker. Any ideas what I can check—either physically in my machine, or via software in dom0?