Mine has the latest firmware applied. I was listening to the 990 with "room 2" turned on (as I often do when I go to bed), and the main room was off. When I woke up I went out into the main room and when powering it up it would temporarily have the power lights blue and then flip to amber (off). Repeated attempts exhibited the same problem.
Not that this is a critical diagnostic factor, but when room 2 is on and room 1 is not, the 990 actually is still powered up (i.e. - blue lights). I do not know if the 990 had completely turned off (amber) over the course of the night since it was my girlfriend who first actually tried powering on room 1 in the morning. I doubt she remembers what color the lights were.
Either way now, from a complete powered off state and even unplugged, to powering it on, it still now never remains on.
I'll do a little more testing in about 1/2 hour.