Sony BlueRay player bugs with non /24 networks

Despite CIDR being an internet standard since 1993, most sony blueray players we’ve tried do not like anything besides a /24 (255.255.255.0) netmask and network. The flaw shows up in particular when attempting firmware updates. Other blueray applications like netflix appear to work ok…

The only workaround is to present the sony device with a /24 network. For example, if the sony blueray player is on the se00 ethernet interface,
you will need to give that entire interface a distinct /24 to play in.

config interface se00
        option 'ifname' 'se00'
        option 'proto'  'static'
        option 'ipaddr' '172.20.4.1' # must be unique across the network
        option 'netmask'        '255.255.255.0'
        option 'ip6assign' '64'

For wifi on the 2.4ghz network instead:

config interface gw00
        option 'ifname' 'gw00'
        option 'proto'  'static'
        option 'ipaddr' '172.20.5.1' # must be unique across the network
        option 'netmask'        '255.255.255.0'
        option 'ip6assign' '64'

You should also change the allowable dhcp range so you can have up to 254 devices by changing the “start” and “limit”
parameters appropriately in /etc/config/dhcp. For se00:

config dhcp 'se00'
        option interface 'se00'
        option start '20' # save some room below 20 for static addresses
        option limit '220' # serve up 200 possible addresses
        list dhcp_option '42,0.0.0.0'
        list dhcp_option '44,0.0.0.0'
        list dhcp_option '45,0.0.0.0'
        list dhcp_option '46,8'
        option leasetime '24h'
        option domain 'mygw.hm.example.org' # whatever subdomain you wish to serve
        option ra 'server'
        option dhcpv6 'server'

And so on. After making these changes you will need to reboot, and probably reboot every device on this network to get the right address and netmask.

Note 1: IPv6 appears to work just fine with modern players with a /64 netmask.

Note 2: most everything else we’ve tried, including the sony playstation and microsoft xbox and google chromecast products, work with a /27 just fine.
If you want more than 30 devices on a given network you can also do the same as above for getting 254 devices