Great news @Gulleucheusch41, congrats on reviving the old IB2 box! π
The one thing I would suggest you to check is that the LAN IP address on the IB2 does NOT conflict with the one from the new router, as the defaults might overlap, and you would NOT be able to access the web interface to configure wifi on the IB2 box.
The DHCP server on the IB2 must also be switched off, as having 2 different DHCP servers on the same LAN is asking for troubles... ππ€£
May I ask you what color the LED is now?
If it's red, then it represents the status of the WAN link. If it's white, then the IB2 checks to see if there is internet connectivity, which there will be via the new default gateway which is the new router. These are just educated guesses of mine, of course!
Anyway, good job! ππ»
And thanks for sharing and giving me a new idea! ππ»
Ciao, Luca