Since puppy was developed, Linux USB support has improved tremendously. As the Linux kernel matured, advances were made in the APIs that the kernel presents to user space. The supporting user space libraries have also evolved in the last five years. Current Linux kernel supports USB3 - well before Windows or OSX. Such improvements have lead to some APIs, such as usbfs, being deprecated.
The main objective behind developing puppy was to create a utility that could be used in embedded Linux devices. Almost all such embedded devices still run older Linux kernels, so I will not be upgrading the puppy code to switch from the now deprecated usbfs implementation to the new sysfs API. I don't really have the means to test the changes. Current Linux kernels still have support for usbfs, you just need to turn it on.
To bring back the
/proc/bus/usb/entries, rebuild your kernel with
mount -t usbfs none /proc/bus/usb
That's all you should need to make your system compatible with puppy.