Privilege Escalation on DPC3008 (and cable modems generally)

I have never done a lot with my cable modem until today. For reasons unrelated to this issue I wanted to change my MAC. Upon visiting my modems web interface I was surprised to find I couldn't do anything. My research indicates that my modem, a Cisco DPC3008, has 3 privilege levels. The web interface I had access to was the one presented to the user, or lowest, level. This is my modem (not a rental), but I am stuck with no privileges. If I am understanding what is going on correctly; my modem is reaching out to my ISP for its configuration (or the complete firmware?) and this is what is locking me in the lowest privilege level. Just to see if I had any control over my hardware I even tried to login to my modem without it being connected to my ISP, only to have my connection timeout. I cannot find alternative comcast compatible firmware to install on my device.

This is probably a naive question, but is there anyway to escalate my privileges on my Cisco DPC3008? Is it common practice for an ISP to cripple hardware in this way?

For the curious; This issue originally started because I was testing my ddns service, Comcast is my ISP so my IP is tied to my MAC and only changes on its own ~9 months or so. So needed to change MAC to change my IP.