God I feel like a noob... I got an Obi200 as a spare and tested it, then put my Obi202 back online and suddenly incoming calls did not ring. It turns out that I had plugged into "phone 2" instead of phone 1, thinking they would both work the same. Now that I plugged into phone 1 my incoming calls ring.
What setting makes phone 2 also ring?
If you want incoming voip.ms calls to ring both phones on your OBi202, go to the Voice Service screen associated with voip.ms (if it's set up on SP1, this would be Voice Services -> SP1 Service) and change X_InboundCallRoute from "ph" to "{ph,ph2}".
Thank you so much restamp, I might never have figured that out!