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I'm not too familiar with customer DSL solutions but for cable modems, that firmware and configuration is managed by the CMTS because technology and configurati

by luma 2y ago

I'm not too familiar with customer DSL solutions but for cable modems, that firmware and configuration is managed by the CMTS because technology and configuration changes on the head end may require customer-side changes to ensure continued operation. The config is a pretty dynamic thing as frequency plans, signal rate, etc change over time as the cable plant and head end equipment is upgraded and maintained. I'd expect that any attempt to lock write enable to the EEPROM would eventually result in your modem failing to provision.

Scoundreller 2y ago
When your provider cuts you off, that’s when you know that your provider has a legit upgrade you need to take. Take the update and then lock stuff up again. Of course, I don’t think you’re supposed to make mods to your vendor provided equipment… In the satellite world, this would happen too: old firmware would be cut off. That’s when you go legit for a while with your sub’d card, take the update, and watch your sub’d channels until the new update could be reverse engineered. And probably have some heroes learn the hard way of taking the update and having some negative impacts that are harder to reverse.
- luma 2y ago
  I'm not sure what such an approach would accomplish. If the goal is to prevent the kind of problem seen in the OP (which, let's be real - is a rare occurrence) in order to avoid an unplanned outage, you've instead created a situation where it'll fail to connect far more regularly as you're kicked off the network for not correctly handling the provisioning process. You're trading a rare unplanned outage for a common unplanned outage.
  - Scoundreller 2y ago
    Depends how often the provider pushes out updates (and the purpose/necessity of them). And it’s only that “rare unplanned outage” when a malicious update bricks your device. Much worse is a malicious update that doesn’t result in an outage. Probably still rare but that impact though. Edit: would also add that there’s probably a big firmware chip that changes infrequently, and frequently changing config stored on a separate and smaller chip (like a 24c or 93 series eeprom that holds a few kilobytes). That way you don’t risk bricking your modem by unplugging it at the wrong time.

by luma 2y ago

Scoundreller 2y ago

When your provider cuts you off, that’s when you know that your provider has a legit upgrade you need to take. Take the update and then lock stuff up again. Of course, I don’t think you’re supposed to make mods to your vendor provided equipment… In the satellite world, this would happen too: old firmware would be cut off. That’s when you go legit for a while with your sub’d card, take the update, and watch your sub’d channels until the new update could be reverse engineered. And probably have some heroes learn the hard way of taking the update and having some negative impacts that are harder to reverse.

luma 2y ago
I'm not sure what such an approach would accomplish. If the goal is to prevent the kind of problem seen in the OP (which, let's be real - is a rare occurrence) in order to avoid an unplanned outage, you've instead created a situation where it'll fail to connect far more regularly as you're kicked off the network for not correctly handling the provisioning process. You're trading a rare unplanned outage for a common unplanned outage.
- Scoundreller 2y ago
  Depends how often the provider pushes out updates (and the purpose/necessity of them). And it’s only that “rare unplanned outage” when a malicious update bricks your device. Much worse is a malicious update that doesn’t result in an outage. Probably still rare but that impact though. Edit: would also add that there’s probably a big firmware chip that changes infrequently, and frequently changing config stored on a separate and smaller chip (like a 24c or 93 series eeprom that holds a few kilobytes). That way you don’t risk bricking your modem by unplugging it at the wrong time.