Pro tip: many that ship with an SD inside will have the factory firmware and device-specific keys still recoverable on the card (secure erase is too slow for production I guess) so before turning the device on for the first time, remove the card and image it for maximum chance of recovering the FW intact.
I would love a DIY open source option but I haven’t been able to find cheap available sensors that would survive a hot car.
Then again if the security really is this bad, maybe you could jailbreak and toss your own firmware on existing cameras. Hmmm
Pro tip: many that ship with an SD inside will have the factory firmware and device-specific keys still recoverable on the card (secure erase is too slow for production I guess) so before turning the device on for the first time, remove the card and image it for maximum chance of recovering the FW intact.