Hello,
Old routers should be used with old builds.
22118 has not proved to be critically buggy in a single case yet.
You should follow the DD-WRT guide to the letter (our home page>Get help>Installation guides)
The guides and articles there were put together based on dozens of hours/cases by IT veterans and work flawlessly in most cases if followed correctly.
If you don’t get a splash page after the wireless node has been set to Unbridged (NAT/masquerade enabled with default zeros all over), and the Services>Hotspot>Hotspot system>DHCP interface>new upcoming wireless node acknowledged by a reboot, then that build will not work.
Regards,
Steve