Yun r2 kernel boot freezes at procd ubus

Running LEDEYun 17.11, r6773+1-8dd3a6e

I rebooted my Yum2 yesterday and it never completed the boot process. Today I managed to get into the boot process using YunSerialTerminal and I watched the boot process. Every time is stops at "procd -ubus".

I can enter failsafe mode by hitting 'f'. So I might be able to recover if I can find out what theproblem is.

Does anyone know what is going on?

Rather than try and solve this, I connected over USB, used the terminal, entered fail-safe mode and carried out a factory reset.

I have no idea what happened. But at least I'm up and running again.