OnePlus 6 won't start: hardware or software problem?
My OnePlus 6 phone went dead. I was using it normally and then it turned itself off and didn't come back anymore. When this happened, it was plugged on USB (usb tethering) and 100% charged.
After that, when I turn it on, it vibrates and the OnePlus logo appears for less than a second (just a flash) and then it goes off again. If I keep volume buttons pressed while powering on, the same thing happpens but with Fastboot logo. I can't get to fastboot mode. I can only get the phone detected in the Qualcomm mode 9008 (holding up key while connecting USB to PC) and I've already tried flashing the stock ROM with MSMDownloadTool and, although the process goes the way it should without any error, after completed the phone reboots and the problem remains the same (I've tried flashing both OOS and HOS files I've found for using in MSMDownloadTool OP6). Note that I only got the device notification light on when flashing the firmware using MSMDownloadTool. Otherwise, that led light is always off.
I've tried a lot of things to revive it, since power cycles (as requested by OnePlus online support) 'til hardbrick procedures as I described above.
Here's a video showing the problem - https://streamable.com/q47bt
Now, after hundred of times trying to turn it on, the symptoms keep the same but instead of flashing the OnePlus logo or Fastboot logo as before, the screen just flashes a low battery message. I can leave the phone connected to the power but it seems that the battery doesn't get charged anymore.
As I'm from from Brazil and I've bought this phone from AliExpress (China), OnePlus official warranty doesn't apply and I'm having trouble trying get warranty from the AliExpress seller.
Thus, I opened the phone and tried myself to find out if the problem is hardware related. I've tried isolating things to clear up the situation: first, I've tried turning the phone on only with the battery (without the USB-type c port charging flex cable connected) and later I've tried to turn the phone on only with USB power (without the battery). In both cases, the same problem described before happens.
So, finally, can anyone help me trying to sort this problem out!?
Should OnePlus 6 turn on without the battery (with USB power only)!?
Although the battery was 100% and seems that only now got discharged after several attempts to turn the phone on, could the battery be faulty!?
Although I wasn't doing any flashing ROM procedures, could this case still be software related!?
Is there anything else that I can try to do to fix my phone guys!?
Thanks a lot!
Is this a good question?