So have set up second hub with a ip outside the dhcp range by one (255) after setting up the black range to end at 254.
I wonder if this is your problem.
According to this
http://www.practicallynetworked.com/networking/convert_wifi_router_to_access_point.htmthe second hub should be
within the first hub's subnet range. The relevant bit (where for you, like in US society
new=black, old=white):
"
Performing the ConversionIn addition to changing general settings, turning a wireless router into an access point consists of disabling its DHCP server and hooking it up to the new router correctly. Start by configuring the general settings. Plug in the old router (but don't connect it to the new router yet) and log into the Web-based configuration utility by typing its IP address into a Web browser. Then at least configure the following settings:
IP Address: Change the IP address to be within the subnet of the new router. For example, if the new router's IP is 192.168.0.1, the old router could be set to 192.168.0.2.Channel: Change the channel to one of the three non-overlapping channels, 1, 6, or 11, while making sure any coexisting or overlapping routers or APs aren't set to the same channel.
SSID: Typically, all the APs of a network should have the same SSID, so roaming works when clients move around and change APs. However, if roaming isn't crucial, think about setting the old 802.11g router to a different network name. This can help the users distinguish between the g and n access; especially useful if performance is important.
Security: Remember to set up encryption, preferably WPA or WPA2, on all the wireless routers and APs.
To turn off the DHCP server, find the DHCP settings, usually on the main or network tab. There should be a check box or something similar to toggle the server on and off; disable it. Then make sure to save the changes.
When the configuration is done, put the old router in place. Then connect an Ethernet cable between them, plugging into the regular Ethernet ports of each. Do not connect it to the old router's Internet/WAN port."
I suspect the reason wired still works is that in that case the white router is acting as a simple network switch and you're essentially just connected to the black router, if that makes sense.