Turning off LED after removing disk drive on R640

I configured a batch of R640 to boot via PXE. Each system came with a hard drive and a raid controller which I ignored during setup. The 640s all boot fine but now I need to remove the hard drives. At poweroff I pulled the drive from a couple of them and powered them back up. They boot find but the system's disk LED is showing amber and the  system status LED is blinking amber.

On one of the systems, I pulled the drive before initially powering it on and the LEDs have never started flashing (they boot from the same diskless image as do the ones that are flashing). I assume that during the initial configuration the system has stored the hardware configuration somewhere and is judging the system health based on that. I've poked around the system setup menus after boot up but couldn't seem to find anything useful. I did reset the RAID controller but after reboot the amber lights still come on.

I'm sure there's got to be something simple to tell the system not to sweat the unused missing drive, but I haven't stumbled upon it yet.