I have installed the latest Volumio for RPI 2.599 on my RPI + Kali + Piano 2.1. It comes up fine when I boot it for the first time (with a LAN cable). After I configure it using the first time wizard, choosing Piano 2.1 as the DAC, it asks to reboot. After the reboot, it is not accessible any longer over the network.
I tried an nmap on the LAN, and it showed just 111/tcp port open (for "rpcbind").