Dreaded Boot Device Not Found error.

[DanTheMan]

Hi all. I have a lovely Zenbook 13 OLED which has been a fantastic little worker for about 2 years now. Yesterday when I pressed the power button I was presented with a lovely colourful screen of Fan speeds, CPU types etc. and after a while I just thought I'd accidentally pressed a function key during boot. Anyway, I clicked save and exit and the laptop booted normally, returned from hibernation and worked fine.

This morning the same thing happened. And I definitely wasn't pressing any function keys. This time save and exit brought up a "No bootable device" error and I went by reflex into panic mode. We've all been here before, right? I just gave the base of the laptop a few gentle taps and tried again and it booted fine. Phew. Then I did a power cycle again with no issues. I ran the self-diagnostic from the Asus app which says all good, whatever that means.

BUT I'm already started to distrust this laptop and backing up HD contents to the cloud.

Any advice on what I should do from here?

Thanks!

[Falcon_ASUS]

@DanTheMan 
Could you please tell me the full model name of the laptop you are using?
How to find Model Name

Based on your description, there might be an issue with the connection between the storage device and the motherboard.
I recommend taking your laptop to a service center for further inspection. 
Sorry for any inconvenience it may be caused. 

[DanTheMan]

Thanks for reply. It's a Zenbook 13 OLED UX325.

I've cycled the power many times now with no issues, but again this morning I accidentally tried to boot while plugged in to one specific charger, a Redmi "fast" phone charger and it went to the boot options screen. It took 2 or 3 restarts to get back to the hibernated state and now all is OK again.

I suspect it is something specific about this Redmi charger that the Zenbook doesn't like.

[Falcon_ASUS]

@DanTheMan 
It might be caused by external devices affecting the power supply to the components on the motherboard. If everything is functioning normally now, I suggest you continue to monitor the situation. Thank you.

[DanTheMan]

I know it's not ideal to use a phone charger for a laptop but my laptop bag is quite slim and the Asus charger sticks out a lot so I try to leave it at home. I never had this problem with a proper USB-C hub though. Another idea might be to only charge with the phone charger while the laptop is off and the components aren't really being used.

Will monitor and report back, hopefully mystery is solved!