Z1S Won't boot, endless "boot" loop in flash-mode when plugged in.

[sreeves212]

Here's my situation:

The phone decided yesterday to shut off. I tried turning it back on and it vibrated once (like it's turning on normally) but then it vibrates 3 times again. No screen, no sound... nothing. I eventually got it to turn back on, not sure what fixed it, but I did open it up and reconnect the battery and press the red reset button.

It worked fine until I woke up this morning and it was off again. Only this time no matter what I do it will not even reach the Sony screen (I've taken out the motherboard, looked at every connection for every part, etc.). I'm familiar with the two boot mode options (volume up and volume down). Neither one does anything.

Here's the weird thing: when it's plugged in it resets continuously, going through the stage of red light coming on, vibrating once, then vibrating thrice. If I hold the up button during this loop, the blue light will come on for half a second.

I've tried flashtool and Sony Bridge. Sony Bridge crashes and flashtool shows this repeated loop:

06/021/2015 11:21:41 - INFO  - Device connected in flash mode

06/021/2015 11:21:42 - INFO  - Device disconnected

06/021/2015 11:21:46 - INFO  - Device connected in flash mode

06/021/2015 11:21:48 - INFO  - Device disconnected

I still feel like there is hope, however. Does anyone have any ideas?

Also, I doubt the volume buttons could be jammed as I tried charging it via USB with the entire button assembly disconnected and it still looped.

Thanks for any help!!

[Thommo]

Try using a windows system and if your bootloader is unlocked then use Sony EMMA

[sreeves212]

Thanks! I will try that, I don't currently have access to a windows system but will try when I do.

I've been fiddling with flashtool still and a huge issue seems to be that the phone resets after a couple of seconds so I can't do anything with it. Do you know of a way I could make it stop resetting?

Here's my last log when I tried flashing it in flashtool (the phone reset itself within a couple seconds):

- Please connect your device into flashmode.

06/056/2015 11:56:09 - INFO  - Device connected in flash mode

06/056/2015 11:56:10 - INFO  - Opening device for R/W

06/056/2015 11:56:10 - INFO  - Device ready for R/W.

06/056/2015 11:56:10 - INFO  - Reading device information

06/056/2015 11:56:10 - INFO  - Phone ready for flashmode operations.

06/056/2015 11:56:10 - INFO  - Current device : C6916 - CB5A1WQ17V - 1277-0679_R14C - 1272-6084_14.4.B.0.56 - TMOUS-LTE_14.4.B.0.56

06/056/2015 11:56:10 - INFO  - Start Flashing

06/056/2015 11:56:10 - INFO  - Processing loader.sin

06/056/2015 11:56:10 - INFO  -     Checking header

06/056/2015 11:56:10 - INFO  -     Flashing data

06/056/2015 11:56:10 - INFO  - Processing of loader.sin finished.

06/056/2015 11:56:10 - INFO  - Loader : S1_Root_6732 - Version : MSM8974_23 / Boot version : S1_Boot_MSM8974_Rhine1.2_LA1.04_19 / Bootloader status : NOT_ROOTABLE

06/056/2015 11:56:11 - INFO  - Processing partition-image.sin

06/056/2015 11:56:11 - INFO  -     Checking header

06/056/2015 11:56:11 - ERROR - Processing of partition-image.sin finished with errors.

06/056/2015 11:56:11 - INFO  - Ending flash session

06/056/2015 11:56:11 - ERROR - S1 Header checksum Error

06/056/2015 11:56:11 - ERROR - Error flashing. Aborted

06/056/2015 11:56:11 - INFO  - Device disconnected

[Thommo]

Looks like a driver issue or the firmware is corrupt but can't be sure

[sreeves212]

My guess is firmware being corrupt as it restarts like this even when not plugged into my computer but through the AC adapter. It also does this when I press the power button while the phone is unplugged but it doesn't loop, it simply shuts off again.

If the firmware is corrupt, do you know of anything I could do about it? I haven't found anything so far.

Also worth noting: when unplugged, holding the power button and volume up does absolutely nothing. The phone doesn't vibrate or anything, very unusual.

-When plugged in to usb, this triggers the fastboot mode.

This is such a weird problem. Even the battery won't charge because the phone does its loop thing when charging.

[Thommo]

If you aren't holding any buttons down and you connect a USB cable and it then enters Flashmode or Fastboot then you have a faulty volume rocker or sticky key

[sreeves212]

I've tried also completely disconnecting the hardware button assembly to possibly eliminate that option. The problem still occurs. When I plug in the phone (even with hardware buttons disconnected) it still goes through this process: 1 vibrate and red light blinks (as if it's normally charging) but then the light goes out and it vibrates 3 times. The process then repeats endlessly.

Interestingly, I connected it to flashtool and played with it more: when I hold down BOTH volume up and volume down while it's plugged into the computer via USB, flashtool reports this: 

06/015/2015 16:15:54 - INFO  - Device connected with USB debugging off

06/015/2015 16:15:54 - INFO  - For 2011 devices line, be sure you are not in MTP mode

It stays in this stage for a minute or two and then goes back to it's normal loop.

I really appreciate everyone's assistance! I hope I can figure this out. 

Also, if anyone has any idea as to how I could make it STAY in flashboot mode for more than a second, I could possibly flash it and maybe fix the problem?

[Thommo]

Flashmode is with the phone switched of hold volume down and connect the usb cable but this does sound like a driver issue or faulty volume keys

[sreeves212 · Accepted solution]

I wish I could say how but my phone works again. I had it completely disassembled thinking it was a hopeless cause and then decided to put it back together a day later and it came on. The system was corrupted but I was able to repair it and I have a fully functional phone now.