cable modem open source

[aular]

Would it be possible for pine to develope an open source cable modem where we can have full access to the whole file system, except the speed file that tells you what you are provisioned for.

[Kevin Kofler]

Unfortunately, that would not be of much use, because (at least around here) it is ultimately the cable provider who decides what cable modem they lend you.

[KC9UDX]

Where is 'here'? I have Spectrum, which is all that can be gotten here. I can use my own modem, and I did for a while. But I deemed it pointless because the router they lend me is included in the price of service anyway. And, with that, I don't have to spend a whole day on the phone when something goes amiss.
Why I don't think am open source router is terribly useful is that I use a router that I control between my LAN and the cable modem. Maintaining that is probably easier and safer than maintaining an open source modem.

[Pavlos1]

It's probably easier (emphasis on the "er") to write a custom firmware for an existing modem.

Someone did a teardown and firmware dump of a couple of Arris modems. The next step would be to try to "jailbreak" the modem by modifying the dumped firmware to e.g. open an interactive serial console on one of the UARTs. The modems are based on a BCM3390 SoC runs Linux so you should be able to get the source code for most of the kernel/userspace (b/c GPL licensing), and work towards replacing the proprietary bits as needed.

If modem manufacturers lock down the SoCs to only run the OE firmware (unlikely IMO), it is possible to obtain new BCM3390 chips from eBay. However, replacing them on existing boards would be a challenge since they are BGA chips. And they're not exactly cheap either.

Re: previous discussion in this thread:

• One advantage of having an open source modem would be resistance to vulnerabilities.
  
• Replacing an ISP-provided modem shouldn't be an issue for most people because the ISP will configure the modem at boot time via standard mechanisms.