[Q] Nexus 4 Blank Screen - Nexus 4 Q&A, Help & Troubleshooting

Hi All,
I have dug, and dug, and dug some more, but I can't seem to find out wtf is going on with this phone.
I was attempting to flash back to stock using these instructions (http://forum.xda-developers.com/showthread.php?t=2010312) on my windows 8 machine. However, after the last step (Step 14 in section D), my nexus simply went blank. And stayed that way. Now, I can tell the backlight is turning on, however nothing is displaying on the screen. Also, my computer is no longer recognizing it. All I can manage to get out of it is my computer is a noise after I hold down power and volume down, along with a red flash of the notification led. The backlight will stay lit, but the screen isn't even turning on. It is also not showing up as a device, adb is simply returning "waiting on device" (or similar), and it is not returning the serial number after typing "fastboot devices".
Is it possible I hard bricked it somehow? I'm at wit's end here. and I would MUCH appreciate any and all help.

Related

[Q] Help! Nexus 7 not working, may be bricked

Hello all,
Recently I have had a major issue with my nexus 7. About a week ago, it died (ran out of battery) while I was using it. When I attempted to turn it on after charging it, I would get the screen that says google, with unlocked lock icon. The tablet would be frozen at this screen. I left it running until it died again. I was running the latest stable release of cyanogenmod 10 with no problems before when this happened.
By now I had realized that the nexus may have been bricked. I did some googling and found that this is an issue other users have been having when their battery died on android 4.2.2. I attempted to restore the nexus. At this time I was able to access bootloader on the device by holding down all of the buttons at the same time. However, I decided not to restore the nexus, and wait until a time where I would be able to turn all of my attention to the problem. But when I tried to restore the device yesterday, I was not able to access bootloader! I connected the device to my PC (running win8) and it is not recognized. Similarly, trying fastboot restart-bootloader gives me "waiting for device". I am afraid that the bootloader may have been corrupted somehow.
My question is, how can I fix this? Is there a way to reflash the bootloader, or is there something that I am missing? Is there a hardware operation that needs to be performed on the device (battery pull, etc)?
Thanks.
AW: [Q] Help! Nexus 7 not working, may be bricked
I doubt your nexus is bricked. Most likely you entered the APX mode. Hold down the power button for about 6-10 seconds, then it should exit from there.
http://forum.xda-developers.com/wiki/APX_mode
Sent from my Nexus 7 using xda app-developers app
Not working
AndDiSa said:
I doubt your nexus is bricked. Most likely you entered the APX mode. Hold down the power button for about 6-10 seconds, then it should exit from there.
http://forum.xda-developers.com/wiki/APX_mode
Sent from my Nexus 7 using xda app-developers app
Click to expand...
Click to collapse
When I hold down the power button, the device just turns off and comes back on again. The google boot logo shows for a few seconds, then I get a black screen.
patil215 said:
When I hold down the power button, the device just turns off and comes back on again. The google boot logo shows for a few seconds, then I get a black screen.
Click to expand...
Click to collapse
If you get a Google logo, that is a good sign - it means the bootloader is at least partially intact, possibly even in perfect shape.
I would proceed assuming that your battery is completely discharged.
Put the device on the charger overnight and then try starting it up while it is still plugged in to the charger. Hold the vol-down button and the power button continuously until at least one second after the Google logo flashes - this should put the device into fastboot mode if the bootloader is intact.
Something to remember is that Li-Ion batteries have a safety feature that prevents them from charging if the battery voltage gets too low. This is part of the reason why they are shipped with a 50% charge - they can sit that way for months and months only self-discharging at a very very slow rate.
OTOH, if you discharge the battery deeply and then let it sit for a long time afterward - especially if there is something like APX mode draining current - the battery voltage can fall below this "safety threshold voltage" and (even though it is still a "good battery" it can no longer be charged).
I'm not sure it the N7 can be started up while plugged in to only the charger; if it can, disconnecting the battery and trying to power up the device might be a way to discriminate "dead device" from "unchargeable battery".
good luck
I've tried this before
bftb0 said:
If you get a Google logo, that is a good sign - it means the bootloader is at least partially intact, possibly even in perfect shape.
I would proceed assuming that your battery is completely discharged.
Put the device on the charger overnight and then try starting it up while it is still plugged in to the charger. Hold the vol-down button and the power button continuously until at least one second after the Google logo flashes - this should put the device into fastboot mode if the bootloader is intact.
Something to remember is that Li-Ion batteries have a safety feature that prevents them from charging if the battery voltage gets too low. This is part of the reason why they are shipped with a 50% charge - they can sit that way for months and months only self-discharging at a very very slow rate.
OTOH, if you discharge the battery deeply and then let it sit for a long time afterward - especially if there is something like APX mode draining current - the battery voltage can fall below this "safety threshold voltage" and (even though it is still a "good battery" it can no longer be charged).
I'm not sure it the N7 can be started up while plugged in to only the charger; if it can, disconnecting the battery and trying to power up the device might be a way to discriminate "dead device" from "unchargeable battery".
good luck
Click to expand...
Click to collapse
I've tried this before. I still get a google screen, even after fully charging it. Does this mean that the battery has become unusable? How can I fix this?
Then try it again. It takes less time than typing a post into XDA.
There are two ways to try it.
1) Hold both Power & Vol-Down simultaneously, and keep holding them down until at least 4 seconds after the B&W "Google" text appears on the screen
2) Hold only the Power button down continuously, but be ready! Press the Vol-Down button as soon as the Google logo appears! - you only get less than a second to do this. (If you are late, the bootloader tries to boot the boot partition). Also, you need to keep holding the Power button down (3 or 4 seconds) after this - wait long enough that you are convinced that the fastboot screen is not going to occur.
As for the battery, you can pop off the back case and use a voltmeter to CAREFULLY measure the open-circuit voltage. The normal 0%-to-100% voltage range is about 3.6v - 4.15v. Obviously if it won't take a charge then there is a battery issue. BE CAREFUL - avoid doing anything which could short the terminals even momentarily.
bftb0 said:
Then try it again. It takes less time than typing a post into XDA.
There are two ways to try it.
1) Hold both Power & Vol-Down simultaneously, and keep holding them down until at least 4 seconds after the B&W "Google" text appears on the screen
2) Hold only the Power button down continuously, but be ready! Press the Vol-Down button as soon as the Google logo appears! - you only get less than a second to do this. (If you are late, the bootloader tries to boot the boot partition). Also, you need to keep holding the Power button down (3 or 4 seconds) after this - wait long enough that you are convinced that the fastboot screen is not going to occur.
As for the battery, you can pop off the back case and use a voltmeter to CAREFULLY measure the open-circuit voltage. The normal 0%-to-100% voltage range is about 3.6v - 4.15v. Obviously if it won't take a charge then there is a battery issue. BE CAREFUL - avoid doing anything which could short the terminals even momentarily.
Click to expand...
Click to collapse
I've tried holding down the buttons in various configurations at least 50 times already. As for the battery, there is current flowing, so I don't think this is a battery issue. Also worth noting is that if the device completely dies and I plug it in again, the charging battery sign appears (an empty battery slowly filling with white bars). Sometimes the device will give a black screen with little white sparks flickering randomly on it.
Well there have been several posts on here with identical symptoms, where the affected owner later reported that their tablet mysteriously started operating normally.
Unfortunately nothing consistent seems to have emerged from those reports.
You could try disconnecting the battery for a few minutes and reconnecting it to see if that makes any difference.
But whatever you do, you're gonna eventually have to press some buttons & the procedure I suggested is diagnostic for the bootloader, even if the boot or /system partition are borked.
BTW In my experience that battery charging graphic shows the charge state of the battery - does yours show closer to empty or full?
bftb0 said:
Well there have been several posts on here with identical symptoms, where the affected owner later reported that their tablet mysteriously started operating normally.
Unfortunately nothing consistent seems to have emerged from those reports.
You could try disconnecting the battery for a few minutes and reconnecting it to see if that makes any difference.
But whatever you do, you're gonna eventually have to press some buttons & the procedure I suggested is diagnostic for the bootloader, even if the boot or /system partition are borked.
BTW In my experience that battery charging graphic shows the charge state of the battery - does yours show closer to empty or full?
Click to expand...
Click to collapse
Mine shows the battery going from empty to full, like an animation. Also, I'm considering sending in the device for repair but I know that since the bootloader is unlocked it probably wouldn't be free.
Also can you link me to any posts related to this? They might be useful in solving my problem.
Thanks
Were you able to get your computer to recognized your Nexus when you connected it? I had to jump through a bunch of hoops with my Win8 machine to get the driver installed, because it didn't pass Microsoft's signature check. Maybe you can use Wug's toolkit to try to fix it, or at least re-lock the bootloader before sending it in for repair?
codehunter2000 said:
Were you able to get your computer to recognized your Nexus when you connected it? I had to jump through a bunch of hoops with my Win8 machine to get the driver installed, because it didn't pass Microsoft's signature check. Maybe you can use Wug's toolkit to try to fix it, or at least re-lock the bootloader before sending it in for repair?
Click to expand...
Click to collapse
After spending a few hours, I was able to get an adb driver installed onto my computer, I also had to jump through a lot of hoops (I run win8 too). Running adb devices shows the nexus in recovery mode. However, I can't access the bootloader whatsoever. Typing fastboot reboot-bootloader just hangs, and I've tried several toolkits but they just hang. I'm not sure if I can do anything unless I can access bootloader. If you know anything I can do please tell.
patil215 said:
Mine shows the battery going from empty to full, like an animation. Also, I'm considering sending in the device for repair but I know that since the bootloader is unlocked it probably wouldn't be free.
Click to expand...
Click to collapse
By coincidence I was charging mine right now (82%), so I shut it down and looked at that battery animation. (I have the v4.18 bootloader & Dec '12 hardware) First the "lightning bolt" symbol shows up in the battery icon, and the a little later, it performs a "filling the battery up" animation. But here's the important part: when that animation runs on mine, it starts from nearly, but not quite full (mostly white, not all black)- about 82%.
Can't tell exactly from the way you described your situation, but this (again) sounds like your battery is either not charging, or the bq27541 charge controller is reporting the wrong battery state.
Unplug the battery and let it sit for a while before reconnecting. If you have a safe way to measure the battery voltage, do so. You'll know right away if the battery is charged and the charge controller chip is lying.
---------- Post added at 08:14 PM ---------- Previous post was at 07:37 PM ----------
patil215 said:
After spending a few hours, I was able to get an adb driver installed onto my computer, I also had to jump through a lot of hoops (I run win8 too). Running adb devices shows the nexus in recovery mode. However, I can't access the bootloader whatsoever. Typing fastboot reboot-bootloader just hangs, and I've tried several toolkits but they just hang. I'm not sure if I can do anything unless I can access bootloader. If you know anything I can do please tell.
Click to expand...
Click to collapse
That is completely bizzare. The only way that a recovery can be started is via the bootloader. If the bootloader doesn't run, nothing can run. (The recovery is a booted kernel just as with the regular OS). Moreover, you saw the battery screen light up - if a recovery was (still) running, you would think something would show on the screen (although I guess recent versions of TWRP does screen blanking now). Very weird.
bftb0 said:
By coincidence I was charging mine right now (82%), so I shut it down and looked at that battery animation. (I have the v4.18 bootloader & Dec '12 hardware) First the "lightning bolt" symbol shows up in the battery icon, and the a little later, it performs a "filling the battery up" animation. But here's the important part: when that animation runs on mine, it starts from nearly, but not quite full (mostly white, not all black)- about 82%.
Can't tell exactly from the way you described your situation, but this (again) sounds like your battery is either not charging, or the bq27451 charge controller is reporting the wrong battery state.
Unplug the battery and let it sit for a while before reconnecting. If you have a safe way to measure the battery voltage, do so. You'll know right away if the battery is charged and the charge controller chip is lying.
---------- Post added at 08:14 PM ---------- Previous post was at 07:37 PM ----------
That is completely bizzare. The only way that a recovery can be started is via the bootloader. If the bootloader doesn't run, nothing can run. (The recovery is a booted kernel just as with the regular OS). Moreover, you saw the battery screen light up - if a recovery was (still) running, you would think something would show on the screen (although I guess recent versions of TWRP does screen blanking now). Very weird.
Click to expand...
Click to collapse
Can I have the links that you mentioned about users having identical symptoms that "fixed themselves"?
I really don't want to send it in for repairs if it's going to cost me. I'm a student with not much money to spare . One of the reasons I bought the nexus 7 in the first place.
bftb0 said:
By coincidence I was charging mine right now (82%), so I shut it down and looked at that battery animation. (I have the v4.18 bootloader & Dec '12 hardware) First the "lightning bolt" symbol shows up in the battery icon, and the a little later, it performs a "filling the battery up" animation. But here's the important part: when that animation runs on mine, it starts from nearly, but not quite full (mostly white, not all black)- about 82%.
Can't tell exactly from the way you described your situation, but this (again) sounds like your battery is either not charging, or the bq27451 charge controller is reporting the wrong battery state.
Unplug the battery and let it sit for a while before reconnecting. If you have a safe way to measure the battery voltage, do so. You'll know right away if the battery is charged and the charge controller chip is lying.
---------- Post added at 08:14 PM ---------- Previous post was at 07:37 PM ----------
That is completely bizzare. The only way that a recovery can be started is via the bootloader. If the bootloader doesn't run, nothing can run. (The recovery is a booted kernel just as with the regular OS). Moreover, you saw the battery screen light up - if a recovery was (still) running, you would think something would show on the screen (although I guess recent versions of TWRP does screen blanking now). Very weird.
Click to expand...
Click to collapse
I also fully charged the nexus 7 overnight. The battery icon now showed no animation because the battery was full (it first showed a picture of the lighting bolt battery, then a picture of a full battery) so I believe that the battery is working correctly.
patil215 said:
Can I have the links that you mentioned about users having identical symptoms that "fixed themselves"?
I really don't want to send it in for repairs if it's going to cost me. I'm a student with not much money to spare . One of the reasons I bought the nexus 7 in the first place.
Click to expand...
Click to collapse
I didn't make a record of them - you will need to search. What sounded very familiar was when you had said
patil215 said:
...black screen with little white sparks flickering...
Click to expand...
Click to collapse
What I recall - probably imperfectly - was that most of those cases seemed to spontaneously resolve when the owner charged their battery. And since your story started out with "black screen and little white sparks flickering", and "low battery" it sounded quite similar.
The various folks who mentioned this said things like "white lines flashing", "like sparks", or "like snow on an old-fashioned TV screen". Don't know if that will help you search, but they are in this forum (Q&A).
I also don't know if their tablets were in one particular mode or another (judging from a PC connected to the tablet - a black screen on the tab doesn't tell you anything) - I don't think any of them reported this.
As I said previously, that Black and White Google logo is produced by the bootloader. I just started my tablet in APX mode right now, and while the "charging battery" icon shows up when using the APX cold-start sequence (Vol-Up+Power), that B&W Google (text) Logo does not show up on the screen - the tablet goes directly from battery charging to APX mode (detected by looking at the PC - device shows up under "Other devices -> APX" in the device manager; VID/PID pair USB\VID_0955&PID_7330&REV_0103
)
So, my point is that it sure seems like your bootloader is there and capable of at least starting up at least part way.
What if your Vol-Down button was not working and you had a borked "boot" partition? If you had that combination, the bootloader wouldn't go into fastboot mode, as it would never see the Vol-Down keypress... and if your boot partition was borked, then you would never get any boot accompanied by a black screen.
At this point I think you should try observing the behavior of the USB port from the PC while trying to start it up... and even though you've tried it before, see if you can get the fastboot screen to appear. Perhaps there is something funky going on with your Vol-down button.
good luck
bftb0 said:
I didn't make a record of them - you will need to search. What sounded very familiar was when you had said
What I recall - probably imperfectly - was that most of those cases seemed to spontaneously resolve when the owner charged their battery. And since your story started out with "black screen and little white sparks flickering", and "low battery" it sounded quite similar.
The various folks who mentioned this said things like "white lines flashing", "like sparks", or "like snow on an old-fashioned TV screen". Don't know if that will help you search, but they are in this forum (Q&A).
I also don't know if their tablets were in one particular mode or another (judging from a PC connected to the tablet - a black screen on the tab doesn't tell you anything) - I don't think any of them reported this.
As I said previously, that Black and White Google logo is produced by the bootloader. I just started my tablet in APX mode right now, and while the "charging battery" icon shows up when using the APX cold-start sequence (Vol-Up+Power), that B&W Google (text) Logo does not show up on the screen - the tablet goes directly from battery charging to APX mode (detected by looking at the PC - device shows up under "Other devices -> APX" in the device manager; VID/PID pair USB\VID_0955&PID_7330&REV_0103
)
So, my point is that it sure seems like your bootloader is there and capable of at least starting up at least part way.
What if your Vol-Down button was not working and you had a borked "boot" partition? If you had that combination, the bootloader wouldn't go into fastboot mode, as it would never see the Vol-Down keypress... and if your boot partition was borked, then you would never get any boot accompanied by a black screen.
At this point I think you should try observing the behavior of the USB port from the PC while trying to start it up... and even though you've tried it before, see if you can get the fastboot screen to appear. Perhaps there is something funky going on with your Vol-down button.
good luck
Click to expand...
Click to collapse
UPDATE!:
Not sure if this will help at all. But I ran adb -d reboot bootloader, and the device just turned off. Completely. I turned it on again by holding power for 15 seconds but I got the exact same thing as before (google with black screen following). Once the device was on and I connected it to Windows, windows said "Windows detected malfunctioning device". But I couldn't duplicate the results again. Running adb -d reboot bootloader just hangs.
patil215 said:
UPDATE!:
Not sure if this will help at all. But I ran adb -d reboot bootloader, and the device just turned off. Completely. I turned it on again by holding power for 15 seconds but I got the exact same thing as before (google with black screen following). Once the device was on and I connected it to Windows, windows said "Windows detected malfunctioning device". But I couldn't duplicate the results again. Running adb -d reboot bootloader just hangs.
Click to expand...
Click to collapse
Incredibly, extra-ordinarily bizzare. ADB on the tablet side is a daemon process that runs in userspace. You would need a completely functional kernel to be running on the tablet, and a functioning ramdisk too in order to communicate with the tablet. ADB does not talk to fastboot mode, nor any other mode of the bootloader.
IF YOU ARE REALLY SHUTTING YOUR DEVICE OFF AND THEN SOMETIME LATER YOU ARE ABLE TO TALK TO THE TABLET BY USING THE adb COMMAND (not fastboot), THAT MEANS THAT THE BOOTLOADER IS SUCCESSFULLY BOOTING SOME (unknown) LINUX KERNEL.
That truly beggars the question of why you are seeing anything on the screen after the google logo. Did the previous ROM not have a splash-screen?
Well, if you can communicate with ADB it might be appropriate to try:
adb reboot recovery
and see what this does.
If you can find the device in the Windows device manager, what would be really, really helpful would be the device VID/PID pair.
The way you do this is like this:
1) Identify the device in device manager; right-click on it and select "Properties"
2) Select the "Details" tab
3) In the "Property" Combo-box pulldown, select the Property Name"
Hardware Ids
If you can get those values we can identify exactly which mode the device is in. There is a decoder ring at the end of the first post in this thread
OK, I'm starting to get fatigued, as I offer up both things to attempt as well as avenues of exploration, and you seem to simply ignore all of it.
I know you have tried it several times, maybe even a million times. Please try both methods of starting the tablet to try and intercept the initial phase of the bootloader startup and see if you can get the tablet to go into fastboot mode.
It's OK to try it and fail. But in all this back-and-forth, not once have you said, "yes I tried it again and it still failed". Try it and report the result, even if it fails.
Please try it again - both methods. In the second method where you click the Vol-Down button only after you see the B&W "Google" text, you need to do it really quickly - and not let your finger off the Power button either for several seconds.
---------- Post added at 06:08 PM ---------- Previous post was at 06:02 PM ----------
PS
The "-d" option to the adb command should only be needed if you were running an emulator via the Google SDK on the same PC.
If that were the case, when you ran the command
Code:
adb devices[/url]
you would see multiple lines of output indicating multiple devices on the machine - one for each running emulator, and one for the actual hardware device (so long as it is actually booted into a recovery or OS and you have the right drivers installed).
bftb0 said:
Incredibly, extra-ordinarily bizzare. ADB on the tablet side is a daemon process that runs in userspace. You would need a completely functional kernel to be running on the tablet, and a functioning ramdisk too in order to communicate with the tablet. ADB does not talk to fastboot mode, nor any other mode of the bootloader.
IF YOU ARE REALLY SHUTTING YOUR DEVICE OFF AND THEN SOMETIME LATER YOU ARE ABLE TO TALK TO THE TABLET BY USING THE adb COMMAND (not fastboot), THAT MEANS THAT THE BOOTLOADER IS SUCCESSFULLY BOOTING SOME (unknown) LINUX KERNEL.
That truly beggars the question of why you are seeing anything on the screen after the google logo. Did the previous ROM not have a splash-screen?
Well, if you can communicate with ADB it might be appropriate to try:
adb reboot recovery
and see what this does.
If you can find the device in the Windows device manager, what would be really, really helpful would be the device VID/PID pair.
The way you do this is like this:
1) Identify the device in device manager; right-click on it and select "Properties"
2) Select the "Details" tab
3) In the "Property" Combo-box pulldown, select the Property Name"
Hardware Ids
If you can get those values we can identify exactly which mode the device is in. There is a decoder ring at the end of the first post in this thread
OK, I'm starting to get fatigued, as I offer up both things to attempt as well as avenues of exploration, and you seem to simply ignore all of it.
I know you have tried it several times, maybe even a million times. Please try both methods of starting the tablet to try and intercept the initial phase of the bootloader startup and see if you can get the tablet to go into fastboot mode.
It's OK to try it and fail. But in all this back-and-forth, not once have you said, "yes I tried it again and it still failed". Try it and report the result, even if it fails.
Please try it again - both methods. In the second method where you click the Vol-Down button only after you see the B&W "Google" text, you need to do it really quickly - and not let your finger off the Power button either for several seconds.
---------- Post added at 06:08 PM ---------- Previous post was at 06:02 PM ----------
PS
The "-d" option to the adb command should only be needed if you were running an emulator via the Google SDK on the same PC.
If that were the case, when you ran the command
Code:
adb devices[/url]
you would see multiple lines of output indicating multiple devices on the machine - one for each running emulator, and one for the actual hardware device (so long as it is actually booted into a recovery or OS and you have the right drivers installed).[/QUOTE]
Sorry for not indicating the results of all of your suggestions.
Believe me, I have probably tried both of your button combinations at least two dozen times already. And I have gone down every avenue of exploration that you've suggested.
I've even tried every single one of the button combinations in the thread of nexus 7 button combinations. When I do anything from when the device is on, after 5 seconds or so the device turns off. Then the tablet shows the Google screen for about 5 seconds, no matter what I do. After the google screen comes a blank black screen (I can tell the device is still on because it's illuminated black, different from if the device was dead or powered off). There's not even a way I can get the tablet to power off - it just automatically restarts even if it's not connected to power, so I have to let it die or do a battery pull if I want to fix it. The black screen remains there indefinitely (until the battery runs out of course).
I've tried disconnecting the battery, leaving it disconnected for 30 minutes, connecting the device to power with the battery disconnected, having the buttons held down and connecting the tablet to wall power and USB pc, and different chargers. Nothing gives me a different result. The battery is alive and working, and the voltimeter did give me a current, sorry for not posting that earlier. About the random sparks/snow, there is really no pattern to when these appear, although they might be more frequent (but it might just be me) after a battery pull or full battery discharge.
Remember, I used to be able to access the bootloader but that stopped working for some reason. I'm kicking myself right now for not restoring the tablet when I was able to access bootloader, but I was busy at the time.
I've had some experience with rooting, locking, and unlocking other android devices, but this is something extremely weird.
Also, I should have posted the hardware ID's of the device before. I had done the exact same thing as you suggested when I was trying to install an adb driver for the nexus 7 (had to jump through a lot of hoops to get it working on win8, goddamn win8). The hardware ID's are USB\VID_18D1&PID_D001&REV_9999 and USB\Vid_18D1&PID_D001. According to the guide this means the device is in custom recovery, which makes sense because I was running Cyanogenmod 10 with clockworkmod recovery. If normally booting into the OS, the tablet should be giving me the default animated Cyanogenmod splash screen. Perhaps this issue is a bug with clockworkmod recovery?
I know that -d is to target a specific device, however I pulled up adb and went through each command methodically (really tedious) to see which ones would work. For some reason adb -d reboot-bootloader was the only thing that gave me a response, and even that won't do anything anymore (it just hangs, same with any other adb command). adb reboot recovery hangs also, and any fastboot command gives me waiting for device. Since I've installed a driver for it, in device manager the device shows up as Android phone and Android Composite ADB Interface. Windows tells me it's working properly (really? I'm not so sure windows).
I'd like to apologize for not indicating the results of trying your suggestions. Believe me, I have been trying them! I've spent probably a total of 12 hours trying to get this damn tablet fixed.
I'd also like to thank you. Without people like you this forum would not be any good. I am really grateful for any advice even if it does not work.
I know this is a hell of a problem. No goddamn clue how this happened. I love android but I sincerely hope that this is a clockworkmod recovery problem because otherwise that would make it a mistake on Google's (and therefore android's part). I know that the battery issues are quite frequent on android 4.2.2, but I have yet to find another user with my symptoms.
Lastly, do you know of some way to lock the device or destroy evidence of having the bootloader unlocked without being able to access the bootloader, in case this can't be fixed and I have to send it in for repair?
Click to expand...
Click to collapse
patil215,
Whew. That took you some time to write - thanks for all the details.
The USB\VID_18D1&PID_D001 USB Device Id sure does look like the custom recovery. I will assume - unless you say differently - that you would see this VID/PID pair any time you had the "black screen but with the backlight on".
Android uses this thing called the "BCB" (Boot Communications Block) to write instructions for the bootloader about what it should do when it starts up the next time. In the absence of seeing this, no doubt the bootloader has a default behavior. But basically, the way this works is that a "reboot" command eventually causes the kernel to write into this non-volatile memory area, and then a soft hardware reset occurs. The bootloader is aware of the BCB, and under normal circumstances, it will read it and attempt to follow the indicated boot mode - and then either erase the BCB or fill it with the "default booting instructions" just prior to booting a kernel or special-purpose mode previously indicated. In this way it will return to it's default behavior the next time it is booted.
The reason I mention it is that I have seen on other devices that got borked (HTC Droid Eris) in a way that sometimes those phones would always jump into a particular booting mode - and ignore any hard-button presses that would normally cause the bootloader to follow a different path. The Eris had/has "bootloader", "fastboot", and "OEM" modes and sometimes borked devices would not boot into anything other than the OEM mode.
So, since you apparently are seeing some evidence that a partially-functioning recovery is running, that sounds like a very similar scenario - the Asus bootloader is always booting to your (damaged?) recovery.
So, that's materially different (I think) than what other folks might have experienced it. The first time I've seen it here, although TBH I've only been looking in here for a little less than 3 months.
I don't know what else to suggest - it sounds like maybe you've tried things like "adb shell" commands?
If the bootloader can't be forced into fastboot mode, that (possibly damaged) recovery mode is the only privileged thing you have left. It seems to me that if you can't get into that somehow - adb being the most obvious route - then there is little left to do.
No, I don't know how to relock the bootloader without using the bootloader. That's probably something that can only be done with factory methods (possibly in APX mode).
Sorry.

Display shows Samsung title then goes black same when going into download mode.

First off I am running 4.2.2 on MF3 with root. I have no custom ROM, recovery or any other modules. This literally just happened 30 minutes ago. I've tried searching everything to no avail. My screen randomly went black (after setting it down for 15 seconds) and now it won't work. When I take out the battery and stick it back in the initial pop up is the Samsung name with an unlocked lock that says custom, this will pop up regardless if I press and hold the power button or do anything, which hasn't happened before. After that screen nothing happens as normal. I have tried to boot into download mode and I can get to the initial "WARNING" screen and then get into the download screen with the Android alien and before anything can happen it will go black. So this leads me to believe that is it either crashing or failing after the initial 20-30 seconds of boot sequence. I will also mention that when I have the USB cable plugged into both a computer and a wall outlet that it wont do anything even after i take out the battery and put it back in, try to boot into download, or just hold the power button. The computer won't even recognize that a device has been connected. When it is unplugged I can do what I previously mentioned. Please if someone can help me I would greatly appreciate it. I am really worried that because I have my device rooted I won't be able to take it in for warranty and get it replaced. Any help is greatly appreciated! Thanks in advanced!
Same happened to my phone
The exact same thing seems to be happening with my phone, however, my phone was not rooted. After installing KitKat (4.4.2) the phone was acting a bit weird and, all of a sudden, the screen went black. Can't turn it back on since then. The welcome screen comes up only after I put the battery in. After that it is completely unresponsive. I am also able to see the download mode warning before the phone goes off on its own, and the same thing happens for the recovery mode. I see the 'recovery booting' message, but then the phone turns off.
AT&T is has replaced my phone, but I wanted to get my data before sending the damaged phone back. As stated above, the phone is not recognized by my computer, so I can't access the data through USB. The guys at AT&T could not help me with the data recovery. If anyone could help me with this, I would greatly appreciate it.
D

Nexus 7 2013 Black Screen

Hi guys. Great forum
I tried to use my device today and it was unresponsive. The device was previously left on with full charge but when i came to use it the screen would not activate as normal. I tried turning the tablet on/off but still the screen was blank. I tried charging it but there was no charge icon.
I assumed a battery issue or some sort of bootloop. I followed the instructions on here to enter the bootloader menu but despite multiple power/volume button combos, nothing happened.
Then (stupidly) I realised the device was still switched on! I only realised this as i received an email and the notification light lit up! I am also able to contact and locate the device using Google Device Manager. So the device is switched on but the screen is dead
The device has not sufferred any physical damage. It was in a bag inside a case for a few hours with the screen locked.
Is there any way round this that you guys know of?
Many thanks in advance.
You might want to try the 2013 forum. They might have run into this before. This forum is for 2012 model
#stayparanoid

Nexus 7 (2012) unrecoverably dead?

I have an old Nexus 7 running stock bootloader/OS, that someone started a factory reset on (possibly by using the hidden 4th button under the casing), but is now stuck on the "Erasing..." mode.
I've tried every button combination I can think of to boot the device into a different mode, but it is determined to always return to this Erasing screen. Is there a nack to accessing the bootloader (I've tried just holding power button and volume down for a very long time, hammering the volume button during reboot, tapping it once when I see the Google white text on black background, but to no avail), or is it impossible from this mode?
Sometimes I'll manage to boot it into APX mode, where the screen is black, but the PC recognizes the device, but I'm not sure what use this is?
This is a picture of the mode I'm stuck in:
http:||imgur.com/57mChOM
Have you checked ADB is working or not. Try with nexus root toolkit, it may help you out.

Smashed Screen + Stuck in Adb Interface = Challenge

Hey guys!
Dropped my phone. Screen is completely black. Charges fine. Fully charged now, notification light went from red to green.
Plug into PC, I hear the Windows USB mount sound, I see option to disconnect. In Device Manager, under Android Devices, Nexus 6p Adb Interface. In abd, no devices listed.
Device was rooted and 100% had debugging enabled, but since the screen went dark, a bunch of buttons were pressed and I have no idea what has happened as a result. If I had to guess.. if is in download, or recovery mode. I can't tell.
Any ideas on how I can regain access without spending money (haha, I know)? I read somewhere that the Nexus 6p doesn't have HMDI out. Is that true? So that wouldn't be an option? I just need to know if fixing the screen will fix the phone. It doesn't appear anything else is damaged, but how do I know for sure?
Thanks!

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