This paper provides a walk-through on using binwalk and gzip to get to the disk image contained within a Sercomm IP Camera .bin firmware update.
You can download it from the following link: https://packetstormsecurity.com/files/download/121713/reverse_engineering_ip_camera_firmware.pdf
Source: https://packetstormsecurity.com/files/121713/Reverse-Engineering-Camera-Firmware.html