cg3000dv2

This is a cable modem gateway combo unit. Also this unit isn't currently listed here:

https://kb.netgear.com/000036375/What-s-the-latest-firmware-version-of-my-NETGEAR-cable-modem-or-modem-router

 

I presume this model maybe EOL and no longer developed with NG:

https://www.netgear.com/support/product/N450.aspx#download

 

Also FW for cable modems are updated by ISPs. Developed by NG then sent directly to ISPs for there testing then the ISP will send it to users modems.