$this->bbcode_second_pass_quote('sdrider', 'U')pdated to 4.9.13-6 tonight. Rebooted, and it came back fine - ie. seems to be back to normal. I rebooted a few times to test it out. It seems to take a little longer to reboot than before - up to 60 seconds, as opposed to ~25 or so before. But after several reboots, it has come back consistently every time without me having to hard power off.
Not ready to upgrade my internet router odroid just yet, but so far 4.9.13-6 is looking a lot more stable than the first few 4.9.13's were a week or two ago.