moto-penangf
Failed attempt to use UART #2
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Is it possible that KPCOL0 is doing something in the UART or allowing us access to it? The test points for this are in a very convenient location. 
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Replies: 9 comments 82 replies
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I tried connecting it via UART:Phone RX <- voltage divider <- TX Arduino And it seems something went wrong and now it won't turn on and it says 0% battery chargevideo_2024-12-21_13-17-10.mp4But it can still be detected by the PC as Preloader and mtkclient detects it
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BE CAREFUL WHEN CONNECTING TO UART!It looks like the battery calibration is off somehow or the charge controller is partially failed. I'm trying every way I can to calibrate it and get it to work. When it's been sitting for a while it can turn on, I really hope it's a calibration error and not the charge controller. |
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It seems that when you hold the device in fastboot mode on the “Barcodes” page, the battery starts to calibrate little by little. It's possible that the battery calibration was indeed knocked off when connected to the UART (LOOOOL, WTF MOTO???) and the firmware won't be able to fix it. The solution to the problem is likely to be to let the device restore the calibration on its own, but the process requires supervision. If I manage to fully restore functionality, I'll be sure to report back and add a section to the documentation. 
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Good news to hear! |
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@progzone122 try using this code in the dial |
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No new information, there is no battery calibration function in this menu.
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Sad that there's no battery calibration mode, but now I can confirm you it's a battery calibration issue 100%, I have the same voltage right now but I'm at 70%, your charging controller is safe I'd say. |
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I have it showing 3.6V/4.0V/3.4V. |
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After extensive attempts, I managed to get the phone to charge at a reduced current (3–5 W). 
Now the device no longer shuts down, but there’s one concern. Motorola moment?When the phone couldn’t boot and showed 0%, there was a sound on the board resembling coil whine. This occurred only when trying to boot into Recovery, Fastboot, or Android, but the sound was absent in the bootloader mode selection menu. What could this be? Is it possible that Motorola intentionally designed it this way, and devices might start failing over time because of this? |
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Sounds like it's trying to pull more current than it should because it detect the battery as dead (drained too much to even power on). |
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Now I'm going to take it apart again and solder a motor or LED strip to the battery, that's the only way to discharge it. |
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video_2024-12-23_02-19-31.mp4 |
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Make sure to check the voltage from time to time to be sure to not discharge it too much |
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The battery has 4.26V, so I can go to bed, I don’t think it will be completely discharged in 5 hours with such a small load |
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Unfortunately, it seems that the power controller or something in its circuitry is half-dead. If I connect it to a charger without the battery, it still won't turn on, but the voltage on the test points jumps between 3.6 and 4.2V, and I can hear some clicks or whistles. This really sucks because I don't have money right now. |
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It's strange that UART messed up something for real though, I mean, aren't UART points just data transmission lines? |
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I don't know, maybe there was a short-term voltage surge and it killed something in the power supply and therefore the components that were working at the limit are now half dead. As far as I understand, there is no protection on the UART line or it works incorrectly! My God, even my router for 400 hryvnia has protection on the UART line |
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I think you're right: if you look at page 13 you see how the UART TP connects directly om the SBS, maybe that's why |
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what idiots they are... |
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Your final hope is that it's just the battery dying for some reason. Booting to preloader and fastboot requires way less battery usage compared to booting to system (sensor, LCD, brightness, cameras and more), and all this stuff could be causing a drop of voltage, so much that the system inits a complete shutdown 🤔. That would explain why overcharged battery is stable but when you drop just a little it shuts down completely. Considering how I found sources claiming that this phone battery swells after just 1 year of usage, it could be a possible scenario. |
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@shomykohai Please provide the device boot logs, maybe I can find the reason in them, because I have logs written to expdb (it is desirable to clear them beforehand). It will help me a lot! |
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Good! Everything is fine, it seems to be a mtkclient or DA file issue. diablo-pc :: ~/Desktop/fuckyoumoto 130 » mtk w seccfg ./backups3/seccfg.img
MTK Flash/Exploit Client Public V2.0.1 (c) B.Kerler 2018-2024
DAXFlash - HW-CODE : 0x707
DAXFlash - HWSUB-CODE : 0x8A00
DAXFlash - HW-VERSION : 0xCA00
DAXFlash - SW-VERSION : 0x0
DAXFlash - CHIP-EVOLUTION : 0x1
DAXFlash - DA-VERSION : 1.0
DAXFlash
DAXFlash - [LIB]: Error on sending parameter: Write data not allowed (0xc002000c)
Failed to write ./backups3/seccfg.img to sector 606208 with sector count 16384.
diablo-pc :: ~/Desktop/fuckyoumoto » mtk e seccfg
MTK Flash/Exploit Client Public V2.0.1 (c) B.Kerler 2018-2024
DAXFlash - HW-CODE : 0x707
DAXFlash - HWSUB-CODE : 0x8A00
DAXFlash - HW-VERSION : 0xCA00
DAXFlash - SW-VERSION : 0x0
DAXFlash - CHIP-EVOLUTION : 0x1
DAXFlash - DA-VERSION : 1.0
DAXFlash - Formatting addr 0x12800000 with length 0x800000, please standby....
Progress: |██████████| 100.0% Erasing (0x4000/0x4000, ) 620.00 MB/s
DAXFlash - Successsfully formatted addr 0x12800000 with length 8388608.
Formatted sector 606208 with sector count 16384. |
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Note, we can't format any of the partitions, this seems to be a DA limitation. |
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It showed 0% again after working for a while |
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It would be good knowing if it is actually the battery or not mmh. |
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To confirm that the expdb partition is not readonly and actually changes, i checked for My guess is that the partition is capped, so after a certain time it deletes old logs, that's why I didn't find red state in your logs: you probably rebooted your device many times compared to me |
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Battery: Is it possible that there is a damaged BMS in the battery? |
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If it makes the device usable again, I'd say yes. |
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Well, since the phone was charging (albeit at a reduced current), it looks like the PMIC is working fine. |
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Good thing I have a spare Mi A2 Lite phone that works great. |
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If only we could boot to this mode: https://www.lieberbiber.de/2015/05/04/hacking-the-bq-part-2-factory-mode/ You could see the PMIC status apparently. Android Utility can send that reboot command, but I only got the boot logo and Windows recognized it as "GdC Gadget VCOM" and then after ~30 seconds rebooted to preloader |
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This is important information! |
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@shomykohai I figured out a way to accurately determine if the battery is working or not. |
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I assume in this case you would only apply voltage to the battery terminals, thus the phone would detect it as if there's no battery connected (0%). You could try tho supplying these voltages to the battery BMS and connect it like that, that would be safer as the BMS should have a protection system (Usually, we can't be sure anymore with this phone, but would still be safer than connecting directly on the MB) |
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I even think you need to apply power ONLY to VBATT_C+. |
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Because when I connect it to the charger without battery, I get floating 3.8-4.2V on VBAT, while on VBATT_C+ - 0V |
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Good idea, on some batteries, this way the active BMS protection might be reset. I'll first try applying power to the battery, and if that doesn't help... |
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I ordered the battery and hopefully they will let me test it at the Nova Post office |
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Yes! Looks like it was a crappy Motorola battery!
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Good news to hear! |
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Yes! The main thing is that my battery died almost immediately after the warranty expired. It's a really crappy device... |
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Yes! Looks like it was a crappy Motorola battery!