I do have exactly the same observations. Therefore, I try not to discharge until 40% and start charging in case it reaches this level.
Still nothing from zendesk either. I have same symptoms as Hans. My C2 only works with external power. I guess I’ll get JP2 before C2 gets new hardware
On my C2, the value of the charge indicator seems to be completely unreliable. The phone reboots often when indicating an energy level like 98%, or maybe even 100%.
After the (connected) restart it then suddenly can indicate a charge like 79% or something in the 60-percent and then “recharges to 100%” at a speed that seems too fast to be true.
I have not seen a battery percentage like forty-ish for a couple of weeks.
By now, I would love to have a predictability like that.
It sounds like a connector/contact problem at the battery port or a weak battery.
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My C2: “fully” charged, start phone, 100%, 10 minutes youtube(brave) battery goes to 84% and then “good bye” shut down. Connect charger, 0%, 30 minutes charging 18% and then few minutes it’s 100% again. Sometimes when I start phone it shows 100% but shuts down after few seconds and when connected ir shows 0%
I have a Sony Xperia 10 iv which is exhibiting the same symptoms. Random shutdowns after using the phone for a while after charging. Some other 10 iv users also report this issue on the forum.
They can’t all be hardware issues surely?
Oh, and another persistent phenomenon I forgot to mention:
- After the first crash, the SIM is not detected.
So I have to reboot it manually for a second time to have that back.
Dunno why fingus removed his remark about corrupted SW after a firmware upgrade, but I was considering the Fastboot firmware reset that I also did before I moved from my Sony XA2 Plus to the C2 as my “production device”.
I’ve been hesitant to try that now that it IS my main device, but given the annoyance from the reboots have lasted for two month’s already, and I 've been updating my notes about the configuration and my tweaks I think it is worth taking a deep breath and taking the shot.
Because I’m not 100% sure it’s the cause. A complete reflash is free and can fix many problems, so it’s up to you whether to try it.
Ah, okay thanks for the explanation.
I think you already expressed the not-100% certainty enough for me in your original text to be aware that it is (at least) an educated guess.
Just finishing backups of production data and started recapturing the C2 firmware reflashing notes
The Jolla shop firmware download was already moved to 5.1.0.11, but I think I’ll keep my local copy of 5.0.0.43 in reserve.
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Applied the complete fastboot flashing procedure with the 5.1.0.11-images, but shortly after restoring the SFOS backup a crash occured and there have been a couple more since then. Some of them even with power connected now (under heavy appsupport activity).
So this does not seem to be a solution, pitty.
It seems hardware fail to me.
More and more I suspect poor manufactoring quality control for C2 in Reeder.
yes my c2 is also dead, it has the same problem
Also pretty worrying that keeping a plug constantly in also increases the wear-out of the C2’s USB-C socket; that’s an important reason why my XA2 became less usable (for the rest: Sony seems to do a a very good job on manufacturing quality).
No response from the Zendesk for more than 2 and a half months.
I 'd expected the C2 to last much longer so no need to join the queue for the new Jolla phone. 
Okay:
Did the test that should rule out regression by 5.0.0.76
Reflashed my device with the 5.0.0.43 image I had used little more over a year ago. It provided an upgrade to 5.0.0.78 and nothing before 5.0.0.76.
I recall annoying problems in 5.0.0.43 so I wanted to prevent getting stuck there but not immediately be thrown into a variant later than 5.0.0.76.
So next thing I tried the image of 5.0.0.72 that I downloaded via the torrent file in
With this image however, the touchscreen after boot was unresponsive, so I switched back to 5.0.0.43 again to see if at least this would fix the crashes.
Had to reflash it twice, because booting it without power connected, somehow distrubed the enrollment process: sometimes it would boot without detecting the SIM card -one of the phenomenon just after the crashes that started last april. So: Bad sign.
After the last reflash of 5.0.0.43 I did sum backup restoration, restored connectivity to my luks-encrypted SD-cars with other backup material that worked, and finally disconnected the power cord and had a crash within some five minutes.
So yes: I bet it’s the hardware.
Reverted back to my old Xperia XA2 Plus from 2018 with the worn out charging port. Besides that I had to get used to a crashless experience again. Sony seems to be much better at quality control.
So got a refurbished Xperia 10III for €150 (The flash was also a bit too tight on the XA2) which runs as a charm for now.
After leaving the C2 disconnected for about a week with a full charge, I plugged it in.
The battery is reported completely empty (0%) and even after a couple of hours on a regular charger it still shows 0%.
Hence it will not boot any more.
Dead as a doornail.
Edit 2026-09-01: WHen taking the device out of the protective case I noticed the battery had swollen noticable for the first time.
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The opening appeared to be a good starting point to carefully pry off the (broken) backpanel. Later I found a youtube that also showed that, and the further teardown (of a Reeder S19 Max Pro) that would enable replacing the battery.
Since Jolla is advertising right for repair of the new phone, I asked them if they can send me a replacement battery for my C2 and possibly an unbroken backpanel (with mounting tape) so I can replace it myself.
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Hello. Have not touched C2 since I got my JP2 1.batch. It’s been waiting in drawer to get some response from zendesk. Still nothing after half a year. Seeing that swollen battery, decided to take a look. And whole long side of back cover is open. So it’s game over. Spare battery would be nice indeed, since looks like not going to get any warranty repair.
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