[adinisom]

Mine used to have the problem. Upgrading the firmware and using Ethernet did not fix it.

Observation: disconnecting the printer from the network avoided the un-wake-able "deep sleep" state. Re-connecting the network made it susceptible again. I suspect it's particular network traffic that causes the printer to wedge into a sleep it cannot leave; possibly a Debian box that I've since de-commissioned. The problem no longer occurs despite having the same firmware as before and being connected to the network.