I misunderstood the instructions on updating the firmware. This is very important (but admittedly confusing):
"NOTE: For the OBi202 ATA Device model, to access the integral local web-page via the WAN port (if prompted), at phone plugged-in, dial: ***0, 30#, 1, 1# and 1."
Basically what it is doing is enabling local web config, which is disabled after the firmware update. I had to pause after entering "***" and listen for obi to respond "Device configuration menu" before I entered "0" (you can enter "0" as soon as you hear the response). When you enter "30#", it should respond with "option 30 current value is disabled...", then you press 1 to enter the new value, then "1#" to enable option 30, then "1" to save the new value.
The "(if prompted)" is what threw me off initially. Nothing prompted me after the firmware successfully updated.