Sam, I would love to see your squashfs dump. Unfortunately your link seems to have expired. Any chance you could upload that again? Also I might be able to provide some assistance on the Sercomm firmware update packages. First take a look at the firmware mod kit:

https://github.com/mirror/firmware-mod-kit
https://code.google.com/archive/p/firmware-mod-kit/

And these two decompiled Sercomm tutorials, both using the FMK:
https://dl.packetstormsecurity.net/papers/general/reverse_engineering_ip_camera_firmware.pdf
http://www.devttys0.com/2011/05/reverse-engineering-firmware-linksys-wag120n/

I also have a few flash_dumper images for the iCamera1000 and iCamera2, as well as update packages from Comcast and Cox. I am currently working on tracking down packages for the RC8021 and RC8026. Let me know if you are interested.