CM600 Issue - Can anyone help?

Good day,

I bought a second hand CM600 which has been locked to IPv6 provisioning. The stupid part is that this apparently "can't be reversed".

Now, my ISP has not rolled out IPv6, and can't/won't communicate any plans for v6.

My ISP kindly tried to assist, but were unable to roll back the MDD setting.

Apparently this setting is applied by ISP's (notably Comcast), which says to me there should be some way to reverse it.

I've opened the housing, and was wondering if anyone could assist me with setting up JTAG so I can poke around?

TIA