I have been playing around with a Technicolor TG799vac that I was given from my isp when I signed up and I have been trying to get access to the file system.
There is a active serial console as I can see all the boot process happen but it seems that the terminal has been disabled, I have so far de-soldered the main flash chip and dumped the file system manually, so I have access to the read-only squashfs https://forum.openwrt.org/viewtopic.php?id=67564 and having a browse through some of the files it looks like it is running a modified version of openwrt.
Is there anyway to re-enable the serial terminal by modifying the rootfs and then re-flashing the NAND and re-installing the chip?