I have four Linksys WRT150N routers configured as access points using WPA TKIP. Since changing my Asus RT16 to TomatoUSB none of them can connect. I went to debug the problem, and I found they can connect using AES, but not using TKIP. I have my RT16 set to use WPA/WPA2 Personal TKIP / AES.
I have tried switch the DD-WRT routers between WPA and WPA2 Personal, but that does not seem to matter. If I use TKIP+AES on the routers that works as well as AES. It is just TKIP which does not work. I do not have a good way of testing if the problem is with DD-WRT or TomatoUSB. The DD-WRT based routers can talk to each other using TKIP, as well as to an older Buffalo router I have using stock firmware.