Posted by pgk pgk on 14/02/2022 11:12:38:
It all started when I unplugged my phone from the PC – the phone died.
No sign of life with the double button reset option, no sign of life with plugging it into a charger and no sign of life leaving it be for a few hours and doing it all again.
…
Just then my old phone spontaneously starts working again.
pgk
I've had similar bother with an MP3 player and two different makes of ebook.
What happens when devices connect with USB is far from simple. There's a handshake to identify what sort of device is attached (GPS, Microscope, MP3 Player, Camera etc etc) and what's supposed to happen next. Plugging a Smart Phone into a USB charger shouldn't attempt anything clever, but plugging into a PC should cause both devices to activate a raft of sensible functionality. It can go wrong!
Catalepsy can be due to the USB comms link being confused by unplugging the cable or powering down before the two machines finish cleaning up after a session. Cleaning up isn't simple either! Failing to eject devices before unplugging is a common cause, but rushing to unplug during an eject is also risky.
Either or both machines may be left confused until an event or timeout forces a reset. The classic 'turn it off and on again' may not be enough to restore order because most modern computers reduce reboot times by remembering previous states, which is great until something goes wrong and a full reset is needed to restore sanity. If the user doesn't know how to force a full reset (it's rarely obvious), waiting patiently may be the answer because computers often watch for stalled processes, which they eventually kill or restart. As operating systems are reluctant to do anything drastic until absolutely sure something is wrong, it may take a few days before before it acts.
I think this is what happened here: the phone went into a coma until a watchdog timer triggered a reset, cutting the knot by forcing a fresh 'don't assume anything' start.
Dave