Map-t on Comcast (SF bay area)?

Have you tinkered w/ map-t on comcast in the SF bay area ?

I'm wondering if there is something Comcast has to configure first. Or if it requires a particular modem (I'm currently using a sb6121, but have a cm600). Or if it needs a particular OpenWRT version (I'm currently running 21.02.1).

FYI, I tinkered a bit. I turned on the log for odhcp6c :

echo 'env >> /tmp/odhcp6c.log' > /etc/odhcp6c.user

... and there are no map-t messages (nor map-e / aftr). Perhaps I need to install the cm600 modem?

Thanks !