Xperia X powers on automatically when connected to charger and gets stuck in infinite boot loop on depleted battery

asked 2020-06-17 23:31:44 +0200

Flox
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Since 3.3.0 (maybe even since 3.2.1, not sure as maybe I didn't hit the problem for a while) my Xperia X gets stuck in an infinite boot loop when connecting to (most) chargers with empty battery. The only way to break this vicious circle is currently a very specific charger/cable combination.

It's caused by a new behaviour. As soon I plug a charger into the deactivated phone, it boots automatically to Sailfish OS, instead of the charging screen as before. While connected to a charger, it even immediately reboots unasked if it's shut down manually. As stated this happens probably since 3.3.0, but I didn't find that mentioned in the release notes of either 3.3.0 or 3.2.1 and also found no configuration option).

What this leads to:

• As soon as I connect the empty device to the charger, it self-activates
• It continues to boot completely, even allowing me to log into the system, just to immediately warn of 0% battery and shutting down
• As soon as it shuts down, it automatically activates... repeat
• This continues for hours if not observed

It happens on various chargers and a power bank I have all used successfully before (and still use with other devices). Only one "magic" charger is still working to start the phone, and only with one of my USB cables it seems. Paradoxically all of them are rated 5V-2A, the power bank 2.1A.

I assume the early automatic immediate boot uses too much power and throws the system back into shutdown. The "magic" charger may just have the little bit extra power output to maintain operation and keep charging a bit during that phase with the lowest resistance cable, weird as it seems.

If I manage to charge the system to 100% (with the "magic charger"... :-( ), the battery life is about 1-1,5 days of usage, so no excessive consumption.

Side note: The automatic boot is a bad feature, at least if its not configurable, as a weak charger (500mA) may well be able to charge the device overnight, but not well support it in operation. Also one may wish to charge faster with the system powered down. And I really like to decide myself when the system is firing up and when not. There ought to be an option to turn it off, and it should evaluate if there is enough power from the charger to support the device.

The phone also even reboots immediately if I shut it down with the charger connected. It will stay down if I shut it down during battery operation though.

Is this even a feature, or is my system disfunctional? Anyone else? If this is a feature, how the do I get rid of it?