The past year I did have some trouble with Error 9 and initialization after power errors (03 or 05). Sometimes, the unit wouldn't boot with the USB drives plugged in, but as soon as they were unplugged, it all started working fine after a few retries. This year it got to the point where multiple reboots after minutes and hours and days, with or without USB drives plugged in or ethernet cables plugged in or rebooting my DACs made zero difference. Error 09 each time. I got a Torx T8 and replaced the CR2032 battery which seems to have fixed the problem.
A note to those changing the cell battery. Pay attention to the +/- sides of both the battery cell along with how the +/- flapper pins are located on the holster where the battery is inserted. One pair of pin makes contact with the bottom side, while the other set of pin makes contact from the top.