That thread helped. Thank you very much!
Apparently the new firmware update really changed SIP phone compatibility settings, but I finally got it working. It seems some new settings were added into the firmware update and values of some existing ones were changed. It took a bunch of tinkering to even get the call into the Obi's call history and get the 488 error. In any event, in my instance, I never had the proxy or registration enabled so those settings didn't matter. Just in case it'll help anyone else, I had to do the following to my configuration for SP2 (where I accept incoming SIP connections to forward to my GV on SP1):
- Uncheck X_RegisterEnable
- Uncheck X_EnforceRequestUserID
- Add a password in AuthPassword
Then on my SIP phone I had to:
- Force use of G711u (on a Linksys/Cisco SPA you need to select it as preferred and then set the "Use preferred codec only" setting)
- Configure the password set in AuthPassword for my Obi SP2 settings referenced above
I was able to set my inbound call route back to what I had and it works now just as it had before. Also, it seems the inbound default SIP port for SP2 was changed by the firmware from 5061 to 5081. Not a big deal - easy to change on the SIP phone or on the Obi.