M2NBP-VM not booting after SATA controller card added

I have a home-built PC that I use to store media files, so I need a lot of HDs. It uses a M2NBP-VM MB, which has 4 sata connectors, and 2 IDE. I have 4 sata drives connected, and 1 IDE HD along with an IDE DVD drive. They all work fine. I'm currently booting off sata1.

I recently purchased an additional sata controller card (the SD-SATA-4P by SYBA). When it is hooked up with no drives attached, the PC boots as it normally does (except, of course, for the controller bios post screen showing for a few seconds at boot). However, if I connect a HD to any of the ports on the controller, the PC will not boot. The controller bios comes up, it shows the connected drive, then goes to a blinking white cursor in the upper left. As I understand it, the PC is 'confused' about where the boot drive is, or something.

I have a 4-in-3 hot swap drive bay hooked to that card, and if I leave the drive pulled out until just after the controller bios shows, then shove it in, Windows sees the drive just fine, confirming (I think) that it's a bios/boot drive issue.

I've checked the MB and controller Bios settings, and have not been able to find any settings which help.

ANyone esle have this problem, or know of a solution?

Well, I feel like a fool.

After some more research, I updated the controller card's bios from 5.3.[something] to 5.403, and it's working fine now.