[One (M7) Q&A, Help & Troubleshooting] MarvThor:
Hello XDA-Forum,

i am new here, so you dont know me. Therefore i have to mention at least one thing about me: I never ask for help. Especially not regarding electronic Devices and Computer Systems. I always found my answers without asking.

Now i do ask for help. Do the math, its a serious problem ;). As i am used to solve my problems before asking for help, i have much to tell before anyone could add to what i already know about this problem (although i have to admit that i am pretty new to the Smartphone World). And as sure as i know that no one here wants to read another "Phone broken, HELP!" Thread, so sure i know that not everyone has the time or patience to read my ramblings (i actually wrote a rant too, but decided not to include it here ;) ). So i prepared a summary, and you can see at a glance (almost) if you could help me at all.

Short Story:

My HTC One is Hard Bricked, and beyond my ability to repair - stuck in QHSUSB_DLOAD mode, no access to partitions, no booting under dead screen. It seems i have to send it in for repairs, but i dont like that(well who does?). I researched the problem, tried every solution i could find - no result! if you happen to know a solution, please read the long story to learn what i have tried so far, and if your solution is something completely new (something i didnt try) - PLEASE tell me ASAP before i send it in for repairs.

So, i tried everything i know of and came to the conclusion: it is beyond repair, at least for me. But as this is against everything i believe in (well not everything but i hope you get the point ;) ) i want to find some other Solution if not for me ( as i need my Phone to be working again soon) then at least for the next one facing the same problem. Again: read the long story, or at least the last part, to know what i am asking for... Basically i want to collect all information regarding this problem and find a solution if possible.

Oh and i would prefer technical answers (even if i might have to learn more to understand them) over answers that suggest "Dont bother, you are a noob, you wouldnt understand, just send it in". If you are about to give such an answer, rethink and do something else ;).

Long Story (Part 1 - What happened):

31/12/2013: My HTC One suddenly stopped working. Until then it worked just fine since i bought it in July 2013. It happened without any apparent cause or any hint of what went wrong, during everyday use, no water involved, no falling, nothing that i could identify as cause. I pressed the power button to wake the phone as always - but the screen stayed black. At first i thought the battery could be empty, but i checked it only 5 minutes before, and it said 32%... still i thought the power indicator could be buggy. Since then it never showed any lifesign again though. It wont start, it wont charge.

I researched about this, and it seems that others had the same problem, and on several different devices. I think i found almost every Qualcomm based device, but mostly the problem was caused by flashing, so this can not be the same problem. If i remember correct, i found HTC One, HTC One S, HTC Desire C, HTC Sensation, Nexus 4/7, Samsung Galaxy S3/S4 and maybe some more, with the same issue i have - Device suddenly went black and got stuck in QHSUSB_DLOAD mode without apparent cause. Many people get at least a lifesign from the LED tough ( be it blinking occasionally, or staying on all the time, or blinking after pressing certain buttons) - i dont.

Long Story (Part 2 - What i tried):

I found several tips on how to revive a device in this state, most recommending something like "press power and one(or both) volume button(s) for XX seconds/minutes" sometimes with the addition to do this under a bright light bulb.

I tried holding the power button, power + vol. down, power + vol. up, power + vol. up + vol. down, for {10,20,30 seconds, or 1,1.5,2,3,5,10 minutes} (countless times), and the same under a light bulb (i doubt this makes any difference as i already did some resets previously, outside in pitch black darkness long before the phone died).

Some recommended to plug it in to charge and dont touch it for 3,8,12 hours - i did that. i tried charging with wall plug and via USB at laptop (for short periods and for 1,3,4,6,8,12,18 hours without touching it).

At the moment i try to leave it off the charger for some days (the weekend and probably some days after) hoping that it will eventually loose all charge and does some sort of reset after that. I doubt it will work, or even be enough time for discharging (as i doubt that it actually USES power in this state) but dont know what else to try before sending it in.

The charging-led stays off when plugged in and there is no response at all from the device. Except when i plug it in at the laptop, Windows recognizes it as QHSUSB_DLOAD. And under Linux i get the Qualcomm device too - no partitions though. If i press power for 10 seconds while connected, it reconnects - so the power button is working. QPST recognizes it as "Q/QCP-XXX (Download)". Is this normal or should it recognize the phone model even in download mode? I tried to get some information through QPST but it tells me the phone needs to be in DIAG mode - which i obviously cant activate on the phone itself. Other than that no life sign at all( also no recognition by adb and fastboot - so its not booting under a dead screen as someone suggested somewhere - dont remember where).

Everyone who had gone as far as i did in trying to revive the phone just gets this last answer "JTAG, or send it in for repair".

Long Story (Part 3 - What i learned):

As i understand it, the Qualcomm Processor switches to this state (QHSUSB_DLOAD) in case there is a severe problem. But i want to know exactly WHAT problem can cause this? And if there is ANY way of convincing the processor to switch to some other state without opening the device?

I dont know JTAG, i never heard of it before this research, so please correct me if i am wrong, i did just a brief research on JTAG and found it too complex to grasp in one or two days ;) i will delve into it at a later time. Here is my first few-minutes-glance at JTAG: it is some sort of standardized hardware-debugging protocol built into many chips, and also the Mainboard or Processor or both in modern Smartphones and Tablets. One would need to open the device and solder the connection cables of a "JTAG-Box" to specific contacts on the Phones Mainboard, is that right? or is there a plug? (I think i found some people using a plug and some using solder iron... i dont remember properly.) When a JTAG-Box is connected to a JTAG-enabled chip, it can issue debugging-commands and/or queries to check (and/or modify?) the functionality of the chip. I found some mentions of JTAG via USB without explanation, is this a way to issue JTAG commands without JTAG-Box over USB Cable? (would be very convenient) Or is it just a way to connect the JTAG-Box via USB to the Computer?

You might ask, if i researched it, i should have every answer, so why am i posting this? Right, i got SOME answers. Now, i know...:

1) ... that am not the first one, nor the only one with this particular Problem. And not even my phone model is the only device with this problem. It might be, all Qualcomm powered devices are possible candidates for a sudden-brick-syndrome.

2) ... some ways to revive a Phone in this state (none working for mine).

3) ... if all reviving tricks fail - JTAG or Repair-service.

4) ... that JTAG needs an opened device (or does it? JTAG via USB maybe?)

5) ... that my phone is not entirely dead: at least the processor can still (sort of) communicate with the PC in

Q

ualcomm

H

igh

S

peed

USB

-

D

own

LOAD

mode.

6) ... no one knows (or tells) what the cause is (or could be) for this problem. The only answers i got are: "There are many possible causes." and "It could be a Software problem" (HTC Support) and finaly "No one can tell without analyzing the device" (HTC and Carrier Support) - Sure no one can definitely tell what EXACTLY is wrong with THIS device... but someone could know what COULD be wrong (What the KNOWN causes are), and just tell me.

Long Story (Part 4 - What i want to know):

Well... I could(/should?) just give in and send my phone in for repairs and hope for warranty. But i did unlock the bootloader through HTCDev (had no other option for unlocking due to HBOOT 1.44) and suspect, they might use this fact to refuse warranty and charge me for repairs, which i might not be able to afford right now. Further, i am feeling absolutely helpless in doing so, and i am NOT used to feel helpless facing ANY sort of problem with ANY electronic device! It is NOT a nice feeling! And i want to change that! Even if it will be too late for me, as i have to get my phone back soon and will probably send it in this week for that reason, i want to find a Solution, that anyone could use to solve this Problem without even contacting the Service, if it is possible to find such a Solution. That is the reason i am posting this, and here is what i want to know:

1) EVERY Story about devices stuck in QHSUSB_DLOAD mode.

1a) IF they where revived and HOW.

1b) What was the cause?

1c) If they could not be revived...

- ... and had to be replaced by a new device: what did the repair team tell what exactly was broken? if they told you anything at all.

- ... and needed replacing parts: WHAT parts where replaced?

- ... ANY hint of what caused the defect?​

1d) WHEN did it happen? (while flashing seems to be the most common scenario, but i and some others had it happen during everyday use)​

2) What exactly is possible to do in QHSUSB_DLOAD mode (probably using QPST)? and what isnt? f.e.:

2a) Pulling any data from the phone without switching to DIAG mode?

2b) Getting ANY information about the phone? (IMEI,CID, etc... Hardware components - i guess it would need a switch to DIAG mode?)

2c) Switching to DIAG(or any other) mode ONLY using the PC and USB connection? (if possible, how?)

2d) Pushing any Data to the device

As i understand it, that is the purpose of this mode(is that correct?), but:

2e) What data can be pushed? Bootloader? System Image? .... i think some CPU firmware is delivered with QPST, correct?

2f) Is it possible to convert an existing System Backup so that it can be flashed with QPST? (i understand QPST needs files in IntelHEX format to push them? Or is that just the CPU Firmware?)

2g) QPST recognizes my phone as "Q/QCP-XXX (Download)". Is this normal or should it recognize the phone model even in download mode?​

3a) If i get no Partitions in Linux while the QHSUSB_DLOAD device is recognized, could this be an indicator for an Hardware failure?

3b) Does it mean, at least the flash memory is fried? (my guess)

3c) Could i tell if the Mainboard was fried by NOT even getting a QHSUSB_DLOAD device? Or can it still be the Mainboard?

3d) Can i tell anything from these facts (Getting QHSUSB_DLOAD device recognized but no partitions)? other than "its a hard burned brick" obviously...​

4a) Which kind of HARDWARE failure could create this state?

4b) and how could that happen during normal use in a device that is only 6 months old, and in good condition?
​

5a) What kind of SOFTWARE failure could cause it?

5b) while it is running? (every day use / not flashing)
​

6)	IF i send it in:

6a) Will they be able to access my data?

6b) Can they tell (by JTAG maybe) if it was rooted,flashed, had an unlocked bootloader?

6c) And the hardware is dead, will they just replace the fried parts? or replace the Phone with a new one? (not really important but nice to know ;) )​

7a)	Is it possible to use ANY type of JTAG commands/queries/(whateveritiscalled) WITHOUT opening the device? (via USB)

7b) Without a JTAG-Box? (already existing software simulating a JTAG-Box)
​

8)	What kind of Information can be gathered by JTAG? f.e.:

8a) Working state of hardware components?

8b) Access to files on flash memory?
​

9)	What kind of modifications/commands can be made/issued by JTAG? (depends on the device/chip attached i assume?)

I know i could just buy a JTAG-Box and learn everything about JTAG to answer some of these questions myself. But i did not find time for learning about something completely new (new for me) yet, and i dont have the money at the moment to just buy a JTAG-Box without knowing how to, and if i will use it (dont even know how much it is...). I will certainly NOT open my 660€ phone, probably breaking the screen and whatever in the process, because of its DONT-OPEN-ME-Design(nice looking, but in some cases inconvenient), and make it a test-dummy for my first JTAGing steps. So it would be nice if someone with some experience in that matter, could give me a brief overview of the possibilities and uses of a JTAG-Box - AND if there is some way to simulate one.

And finally i would like to get into contact with people who might have a clue of the possible causes for this problem, and the ability and willingness to work on a solution. I did find some WIP Unbricking Projects also working on a solution for QHSUSB_DLOAD related issues, but all of them where Model-specific (and mostly for cases where a specific flashed software was the cause) and none for the HTC One (M7)... Although i would like to have a general solution for every device and cause, i doubt there would be any Model-specific Project if it was POSSIBLE at the moment to provide a general one. It would be nice though, if we could at least TRY to make one(some people probably are already trying). But i assume (from what i read) that the existing unbricking projects still need access to the internal storage. So, no access to storage = hardwarefailure & not unbrickable by software?? Even if thats the case and my phone is realy beyond (sofware)repair, i would still like to get answers to my other questions! ;)

If you did read all of this - Congratulations! Have a coffee and a break ;)

I am sorry for:

- noob questions (if there are any left besides the JTAG related - i cant tell anymore)

- annotations and supplements in braces (it can be annoying, i always squeeze in some thoughts somewhere)

- forcing you to read this wall of text, probably full of spelling and grammar errors (i am tired and somewhat tense)

- bad English (not my native language, and... i am tired)