I've been trying for a while to make a printer work with my OpenWRT router, it's a Epson L3150 and it works only with WPS. Currently that button resets the router. Is there a way to make it so pressing that button enables WPS temporarily? Most of the threads i saw on the subject were really old or presented conflicting instructions.
From what I can find, that should be a function in hostapd, which should be part of wpad. Did you uninstall the other wpad package (wpad-basic, wpad-mini, etc.) before installing the full wpad? I'm not sure if that's necessary, but it's worth a try.
I remember reading on a tutorial specifically telling me to uninstall wpad-mini, then installing the full package. Right now only wpad is currently installed.
Have you tried rebooting your router after installing wpad? It really does look like it's not working properly to me. If issue persists after the reboot, can you post the list of installed packages? It's either opkg list-installed or apk list --installed depending on the OpenWRT version.