L5 runs hot and red LED starts flashing fast 5x-off-5x-off-

We established in an earlier thread that this “85℃” was not a real temperature reading, right?

Yes, 85°C maps to the reading of exactly zero in the charger’s temperature register. Recently there were some fixes related to how the temperature is getting read by the driver (both by us and by other kernel devs upstream), and as far as I’m aware incorrect temperature readings should be fixed now in 5.15, but maybe something is still missing somewhere.


Yes, there must be something broken. If you look at the graph in the screenshot attached above the temp goes down to the level of the others and jumps up again to 85°C

At now I have the same problem.

2 days before battery working well but after when I trying to charge phone I see slow blinking RED, I stop charging and power off phone.
After hour I try to power on phone and it show me that battery not found!
I restart phone and it start fast blinking RED. Press power button and phone going to bootloop 3 times and wont power on.
At next day I charge phone without power on. And now phone always show 85* at bq25890-charger.
Last update nothing change.

Also phone always hot and always loose 40%/hour.

@q4o449, Did you try taking out the battery, and then putting it back in? I found that reset something on my L5USA, that allowed it to power on.

On a few occasions when I couldn’t get the L5USA to start, I had to follow this complicated procedure:

  1. unplug the USB charging cable,
  2. hold down the Volume Up button,
  3. press the Power button for 19 seconds while still pressing the Volume Up button,
  4. plug in the USB charging cable,
  5. finally, press the Power button to start up the phone

I have no idea if this is normal, since my L5USA had manufacturing defects and had to be sent back for repairs, but you can try it.

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…which with up-to-date u-boot can usually be replaced with a much simpler one:

  1. Unplug USB.
  2. Hold the power button for about 20 seconds (or until the LED shines up)
  3. Plug in the provided USB-C PD charger (or another PD charger that’s known to negotiate enough amperage at 5V when used with Librem 5 - the one included in the box does 3A)

That complicated procedure can be useful when the battery is completely depleted, but personally I didn’t have to use it for many months now.

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Phone working (charging working too), but bq25890-charger without USB charge cable always show 85*C.
I have a L5 from latest delivery batch (end of 2021) not USA.

Now I want to check does bq25890-charger still working with old kernel bu I cant find a correct way to try boot prevision kernel…

I correct understand:
What I have installed:

ii linux-image-5.13.0-1-librem5 5.13.19pureos5
ii linux-image-5.15.0-1-librem5 5.15.9pureos1
ii linux-image-librem5 5.15.9pureos1

I just need change symlink /boot/stb to dtbs/5.13.0-1-librem5/freescale/imx8mq-librem5-r4.dtb?
I see L5 still dont have a tested bootloader menu?
Have I any chance to fix /boot partition if I make mistake or something going wrong? (create backup or maybe boot from SD)
Can anyone give me a link where to find instructions or learn how to L5 booting?

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No boot from SD. (I believe it is doable via a chain boot but if you break the content of the eMMC drive then you may not be able to boot from SD either.)

Jumpdrive is what you want. With Jumpdrive you can create a backup (image the entire eMMC drive) so, worst case, if you break it badly then you can restore the image of the entire eMMC drive. If you break it just a little bit then you can telnet in while Jumpdrive is booted and potentially fix whatever the problem is.

(Yes, if you are careful and know what you are doing, you can probably image just the /boot partition. That will be much faster to do the backup and, if required, to do the restore. However I always think that having a full backup is good for any computer.)

I am pretty sure that this is just a bug. Any time you see such a reading, you should assume that it is bogus.

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I trying understand why value wrong.

Today I charge L5 to maximum offline and bq25890-charger now show temperature correctly. I nothing change. Reboot many times - at now problem gone.

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If you are running byzantium then a Purism developer says above that this was literally being fixed as we speak. So maybe an update slipped in to your phone over the last few days.


Just reminding here not to charge the BPP-L503 battery above 4.2V:

Thanks @dos!

P.S. I finally understood this very important advice.


Yes, you can always boot from USB (uuu).

No. Problem appears after all updates and was no longer any updates. I switch off autoupdate and control it myself.

Thanks for advice. But I dont charge battery out of phone. Excuse me, I expressed wrong, I mean that phone charged in poweroff mode to the status when RED light is off (100%) and bq25890-charger sensor now magical fixed (I dont install any updates).


I started this thread because, as the title of the thread says, the device gets hot by having some page in the browser and, perhaps due to the temp., the red LED starts flashing, reproducible.

Why this thread was high-jacked with other questions, problems and hints.

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Brings me to… according to my understanding of:

at least this smaller “issue”, at least one of five values you provided, is gone away. As @q4o449 kindly informed us about the method he/she used, as clearly described (sounds as quite reliable to me) within above related post, as related to 85°C value (I guess). If same described method works for you as well, you might post here new screenshot, reproduced one within same environment, same as described within your initial post (so we can move on).

I working in L5 without rebooting and drain battery to 59%. After that I run monitor and see again 85C in bq25890-charger. I poweroff L5, cooling L5 some hour, power on and bq25890-charger still show 85C.

I charge L5 without poweroff and rebooting to 75% and bq25890-charger work again (with and without USB charging).
Seems there is a battery charge border (between 59%-75%) below which begins bq25890-charger return invalid data.
So lets testing: During self discharge beginning at 70% bq25890-charger several times showed 85C and back to normal. Duration of Interval with 85C is random from 5 seconds to 20 second. At this time (65%) enabling WiFi causes 85С and disabling WIFI leads to normal after few seconds. At 62% I catch very long interval of 85C to 60% battery.
Self discharging of L5 very fast about 1% by 1.5-2 min at screen of Termal graph. I have no SIM and HWoff cellular (HW switches: off/on/on) and SWoff bluetooth, auto-brightness: off. Enabling/disabling WiFi has no visual affects to speed of discharging but case 85C bug earlier. Phone always warm and I dont see any correlation of 85C bug with real temperature of L5.

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Ah, that may be because bq25895’s ADC readings are specified to not work below the VSYS_MIN voltage (which we set quite high by default - 3.7V). I’ll check whether that includes the temperature, but from what I remember I’d say it’s likely that the answer is “yes”. If that’s really the case, then well - just ignore these readings :stuck_out_tongue:

Maybe borrow a Non-Contact Infrared Forehead Thermometer from the nearest place where COVID regs require them to use one and get “ground truth” values. :wink:

I had the same problem with the LED blinking 5x-off-5x, phone getting hot, battery discharging at a rapid rate and bq25890-chager temp showing 85.00°C in the Usage app. The phone’s kernal is on 5.16.11 and the battery life was around 4h.
I followed the instructions about charging problems, not thinking that it was very relevant, but now the bq25890-chager temp is at 40.00°C, the phone’s not as hot but battery drainage is quite significant. While typing this answer the battery is down 10%, from 82 to 72. Don’t know if this is a hardware fault or what to think of it.

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Up to here linked page recommendations it is written: “Birch 8. When the red light turns off the battery is fully charged.” Please poweroff your Librem 5 Evergreen while on and (still) connected to its original power supply and wait until constant red LED light turns completely off. This should help to reestablish 100% of your Librem 5 battery capacity (up to 4.20V recommended max.). Charging rate should be around 5V/1.5A, even 5V/1.6A if your battery still healthy and not taking too long (such powered-off device charging will take several hours but might help with this quick discharging/drainage you described in your post, I hope so).

I needed to edit this post as same procedure already recommended in this thread: