Well, kinda. I just figured this one out. Yeah, you’ll need to plug it onto the laptop chassis, but I think the solution isn’t specifically that you need the laptop chassis or a battery per-se - there’s a BIOS setting called “standalone mode” which needs to be toggled ON for the first time in order for the board to work inside the Cooler Master case. The BIOS setting might’ve defaulted to only allow the board to function inside the Framework laptop chassis…which should probably be mentioned somewhere on the pack-in booklet, or they should ship the board with the option toggled off.
Edit: After togging standalone mode ON, saving the setting to BIOS and pulling the board off a laptop chassis and back on the Cooler Master, it’s still not working. Same alternating red/blue LEDs and no bootup. Eeeeeh…is it a power brick issue or something else entirely? I really want to avoid swapping boards more than necessary.