One of my KPs stopped working, dead, this morning.
I cycled power to the GC and MPS4 a few times, then I updated MPS4 FW, and then downloaded the newest version of the Configurator SW (2.66p), loaded it to the GC, and nothing. KP still wouldn't work.
So, I unplugged the KP and plugged it back in, and it instantly worked. I think I'll try that first next time.
I researched last.fm a little, and it seems to me that's it doesn't have much benefit, for me. Looks like it tracks your listening habits, and shares it with your friends, and offers stations similar to Pandora (Radiohead Radio). I removed last.fm from the iOS app.
Eager to read of Spotify functionality, with the KPs.