I believe the newer software has real limits on the number of connections.
Instead of trying to support more, and give all sorts of odd behavior when
resources run low, it limits to what it can reasonably support. Simple and cheap
external Wi-Fi devices can handle that much better than the chip in the Pi. It
is designed to be a client device and was only able to be a limited function
hub.
-Ken Cameron, Member JMRI Dev Team
www.jmri.org
www.fingerlakeslivesteamers.org
www.cnymod.com
www.syracusemodelrr.org
Ken Cameron