I have an old Xperia XA2 with SFOS which I don’t use anymore (but I’d like to keep as it is).
One issue I noticed with it is that its battery tends to self-discharge to 0% in about a month (when I was using it actively, the battery was still in decent condition and able to keep the phone running for at least a couple of days).
The annoying thing is that when I plug it to a USB charger, the device immediately boots to full SFOS,
only to detect that the battery is at 0% and so it forces a shutdown.
And then immediately it re-boots up, and then re-shuts down… in a infinite loop, unless the USB charger is powerful enough to be able to provide enough power to not only booting up the system but also to accumulate some charge to the battery.
Then after several painful reboot cycles, it might be able to stay up with 1% charge and complete the charging.
As I remember SFOS should be able to ring an alarm even in device is turned off, so is that one the cause
for the rapid self-discharging? If it is, would it be possible to disable the function?
I guess this might be hardware specific. My Blackberry Passport also discharges at a similar rate. The SE Passport models are known to be affected whereas other models (Passport in black) does not autodischarge. After self discharge, the device must be charged at least 30 min before it can be booted at all.
Based on your description it seems the device is really fully discharged without any reserve for alarm or so.
Would be good if autostart of SFOS could be prevented when you plug in the charge …
Had similar situation with one of my Xperia 10’s some time ago.
So I did this:
Use a powerful charger 5V / 2,4 A
Use a thick charging cable.
Connect cable to phone
When it boots, wait until first question for phone code comes
Enter nothing, let phone lying on table and wait an hour.
Let battery charge.
After one hour the battery should be charged enough to normal boot the phone.
The power consumption of the phone should be low enough while only waiting for the first code input, so that enough power remains to charge the battery to a level that phone can be operated.
I do exactly that but even without typing any code (and actually also starting with a phone in ‘airplane mode’ and keeping screen off) it won’t be able to stay on and will do that loop described above a few times anyway.
Might be hardware specific, indeed. I have a number of other old devices, but they hold their battery charge much better. As some point I’ll reflash this one with stock Android and see how it fares.
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