[Q] Nexus 7 Bricked, can't access Bootloader or Fastboot

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awhite2600

Member
Jun 28, 2012
15
3
London
I think I may have my Nexus 7 (2012) in a badly bricked state.

I was running Android 4.3, unlocked and rooted with stock recovery. The tablet froze while using GMail. Pressing the home or back buttons just gave me a black screen with the buttons "highlighted" by circles. I waited several minutes and decided to just power off the tablet. When I looked over about a half hour later I saw that the tablet was frozen on the white Google screen. Two more reboots produced the same result.

I did some research and determined that it might be a good idea to try a cache wipe. I booted into the bootloader and selected Recovery. The tablet rebooted to an android on his back with a red triangle and the words "No command" underneath. Attempting to boot back into the bootloader (Power, Vol+, Vol-) produced the same results - red triangle and the words "No command". I could no longer boot into the bootloader. Powering off and powering on normally also takes me to "No command".

I discovered that I can press Power & Vol+ while in the "No command" state. Doing so produces the following text at the bottom of the screen:

E:Can't open /cache/recovery/log
E: Can't open /cache/recovery/last_log
E: Can't open /cache/recovery/last_install
E: failed closing /dev/block/platform/sdhci-tegra.3/by-name/MSC
(I/O error)


I get a menu at the top with the options to reboot, apply update from ADB, wipe data/factory reset and wipe cache. Attempting to wipe cache produces:

-- Wiping cache...
Formatting /cache..
Cache wipe complete.
E:failed to mount /cache (Invalid argument)
E:Can't mount /cache/recovery/last_locale


After a few minutes I boot back to the red triangle android.

Attempting a factory reset produces:

--Wiping data...
Formating /data...
Formatting /cache...
Date wipe complete.
E:failed to mount /cache (Invalid argument)
E:can't mount /cache/recovery/log
E:Can't open /cache/recovery/log
E:failed to mount /cache (Invalid argument)
E:can't mount /cache/recovery/last_log
E:Can't open /cache/recovery/last_log
E:failed to mount /cache (Invalid argument)
E:can't mount /cache/recovery/last_install
E:Can't open /cache/recovery/last_install
E:failed to mount /cache (Invalid argument)
E: failed closing /dev/block/platform/sdhci-tegra.3/by-name/MSC
(I/O error)
E:failed to mount /cache (Invalid argument)


I've tried using the apply update from ADB option. I can use adb devices to see the serial number. Fastboot doesn't seem to respond and won't list the device. Flashing the factory 4.3 image (downloaded from Google and unzipped) using adb sideload uploads the image and then produces the error:

Finding update package...
Opening update package...
Verifying update package...
E:signature verification failed
Installation aborted.

...followed by all of the "cache mount / open errors shown previously"

Not sure what else to try. (I'm learning all of this as I go from reading posts on this site.) Is there a way to adb sideload the recovery partition as I suspect that it is corrupt?

Sorry to be so long winded. I figured that too much info was better than not enough. Any help would be greatly appreciated.
 
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Remcotjuuh

Senior Member
Aug 7, 2012
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So you can still access the recovery menu? That surely means that your tablet isn't bricked and if you can access the recovery, then you too must be able to access the bootloader. Power off your tablet and try to boot into fastboot by using power and volume -, volume + isn't necessary. Are you sure you have also installed the drivers for fastboot mode? Then try to flash the factory images using the guide here

http://forum.xda-developers.com/showthread.php?t=1907796

Sent from my Nexus 7 using xda app-developers app
 
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awhite2600

Member
Jun 28, 2012
15
3
London
So you can still access the recovery menu? That surely means that your tablet isn't bricked and if you can access the recovery, then you too must be able to access the bootloader. Power off your tablet and try to boot into fastboot by using power and volume -, volume + isn't necessary. Are you sure you have also installed the drivers for fastboot mode? Then try to flash the factory images using the guide here

http://forum.xda-developers.com/showthread.php?t=1907796

First - thanks for responding.

To answer your questions. No, I can't access the recovery menu. It doesn't matter how I boot - power button only, power button and vol-, vol+ or power, vol- only --- the device immediately boots to the android on his back with the red triangle. I don't get the normal "menu" where I can use the buttons to choose and select recovery mode. Sometimes there are the words "No command" under the android, sometimes there isn't. I can't get the tablet into fastboot mode.

When the device boots to the android + red triangle, the only thing I have been able to do is push power, Vol+ which gets me to the menu with

  • reboot system now
  • apply update from ADB
  • wipe date/factory reset
  • wipe cache partition

The "wipe" options fail with the text shown in my original post. If I select "apply update from ADB" it puts the device into ADB Sideload mode. (Not normal ADB mode.) My only option here is to ADB sideload images. I have tried sideloading the factory image. The image transferes, but it fails with a signature error and won't install. I have downloaded the image several times directly from google.

I have uninstalled and reinstalled the drivers a few times. I've used the article that you referenced, another article on this site and used the Wugs Nexus Root Toolkit to install the drivers. I know that my drivers were good originally as I used them to root the device.

Could the errors that I am seeing when I attempt the wipe options indicate a hardware issue? The device seems to be attempting to mount the cache and other partitions and can't.

Additional help is greatly appreciated. Thanks.
 
Last edited:

xbt-

Senior Member
Aug 8, 2013
149
53
Moscow
First - thanks for responding.

To answer your questions. No, I can't access the recovery menu. It doesn't matter how I boot - power button only, power button and vol-, vol+ or power, vol- only --- the device immediately boots to the android on his back with the red triangle. I don't get the normal "menu" where I can use the buttons to choose and select recovery mode. Sometimes there are the words "No command" under the android, sometimes there isn't. I can't get the tablet into fastboot mode.

When the device boots to the android + red triangle, the only thing I have been able to do is push power, Vol+ which gets me to the menu with

  • reboot system now
  • apply update from ADB
  • wipe date/factory reset
  • wipe cache partition

The "wipe" options fail with the text shown in my original post. If I select "apply update from ADB" it puts the device into ADB Sideload mode. (Not normal ADB mode.) My only option here is to ADB sideload images. I have tried sideloading the factory image. The image transferes, but it fails with a signature error and won't install. I have downloaded the image several times directly from google.

I have uninstalled and reinstalled the drivers a few times. I've used the article that you referenced, another article on this site and used the Wugs Nexus Root Toolkit to install the drivers. I know that my drivers were good originally as I used them to root the device.

Could the errors that I am seeing when I attempt the wipe options indicate a hardware issue? The device seems to be attempting to mount the cache and other partitions and can't.

Additional help is greatly appreciated. Thanks.

Is it under warranty?
 

cmason37

Senior Member
May 31, 2012
564
122
Woodbridge
Your cache partition is corrupt. Because cache is corrupt, your N7 probably can't boot anything but recovery. Did your N7 turn off while you were wiping cache or something?

Sent from my Nexus 7 using Tapatalk 4
 

AndDiSa

Senior Member
Dec 2, 2009
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Heidelberg
Looks to me as if your boot / system is not working or corrupt. But you are writing you boot always to the dead Android, that's the bootloader mode and from there you should be able to flash a new system by fastboot. As long as you can go to bootloader there is hope for your device unless some hardware defect prevents you from flashing the system images. Try to install the fastboot drivers for your OS and then try to flash the system images. Probably you need to unlock your bootloader first.

Sent from my Nexus 7 using xda app-developers app
 
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Remcotjuuh

Senior Member
Aug 7, 2012
399
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Looks to me as if your boot / system is not working or corrupt. But you are writing you boot always to the dead Android, that's the bootloader mode and from there you should be able to flash a new system by fastboot. As long as you can go to bootloader there is hope for your device unless some hardware defect prevents you from flashing the system images. Try to install the fastboot drivers for your OS and then try to flash the system images. Probably you need to unlock your bootloader first.

Sent from my Nexus 7 using xda app-developers app

He has already said he can only boot into stock recovery, not bootloader.

Sent from my Nexus 7 using xda app-developers app

---------- Post added at 12:08 PM ---------- Previous post was at 12:07 PM ----------

Now I got myself thinking, the factory images fail, but what about an image for a custom recovery? Try to adb sideload yours from www.clockworkmod.com/rommanager. Is your bootloader unlocked?

Sent from my Nexus 7 using xda app-developers app
 
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awhite2600

Member
Jun 28, 2012
15
3
London
Your cache partition is corrupt. Because cache is corrupt, your N7 probably can't boot anything but recovery. Did your N7 turn off while you were wiping cache or something?

Sent from my Nexus 7 using Tapatalk 4

The tablet froze during normal operation. (Checking GMail.) I simply turned it off...or so I though. When I looked over about 30 minutes later it was stuck on the white "Google" screen. I was able to boot into the normal bootloader at this point. My thoughts were to then select stock recovery and just wipe the cache. It's been in the "red triangle" and "No command" since then.
 

awhite2600

Member
Jun 28, 2012
15
3
London
Looks to me as if your boot / system is not working or corrupt. But you are writing you boot always to the dead Android, that's the bootloader mode and from there you should be able to flash a new system by fastboot. As long as you can go to bootloader there is hope for your device unless some hardware defect prevents you from flashing the system images. Try to install the fastboot drivers for your OS and then try to flash the system images. Probably you need to unlock your bootloader first.

Sent from my Nexus 7 using xda app-developers app

The bootloader is unlocked. I was rooted with stock recovery. I have uninstalled and reinstalled drivers several times. I know for certain that the ADB drivers are installed. I don't have an easy way to confirm that the fastboot drivers are installed - but they should be.
 

awhite2600

Member
Jun 28, 2012
15
3
London
He has already said he can only boot into stock recovery, not bootloader.

Sent from my Nexus 7 using xda app-developers app

---------- Post added at 12:08 PM ---------- Previous post was at 12:07 PM ----------

Now I got myself thinking, the factory images fail, but what about an image for a custom recovery? Try to adb sideload yours from www.clockworkmod.com/rommanager. Is your bootloader unlocked?

Sent from my Nexus 7 using xda app-developers app

I can try sideloading a custom recovery. I may have already tried this...I've tried so many things. I will try again.

The link that you provided points to .img downloads. I thought that ADB Sideload only worked with .zip images. Am I wrong?
 

awhite2600

Member
Jun 28, 2012
15
3
London
I can try sideloading a custom recovery. I may have already tried this...I've tried so many things. I will try again.

The link that you provided points to .img downloads. I thought that ADB Sideload only worked with .zip images. Am I wrong?

He has already said he can only boot into stock recovery, not bootloader.

Sent from my Nexus 7 using xda app-developers app

---------- Post added at 12:08 PM ---------- Previous post was at 12:07 PM ----------

Now I got myself thinking, the factory images fail, but what about an image for a custom recovery? Try to adb sideload yours from www.clockworkmod.com/rommanager. Is your bootloader unlocked?

Sent from my Nexus 7 using xda app-developers app

I tried sideloading the clockwork recovery. The .img file transfers. The Nexus 7 then displays:

Finding update package...
Opening update package...
Verifying update package...
E:signature verification failed
Installation aborted.

:
followed by all of the E: can't mount/open cache/recovery messages as mentioned in my initial post.
 

Remcotjuuh

Senior Member
Aug 7, 2012
399
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Groningen, the Netherlands
Then I'm getting to a dead end here too. I guess you have tried flashing the bootloader too? And how about using the "flash-all.bat" in the factory images package?

Edit:

Maybe sideloading the zip from the images package that contains boot, system and recovery?

Sent from my Nexus 4 using xda app-developers app
 
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awhite2600

Member
Jun 28, 2012
15
3
London
Then I'm getting to a dead end here too. I guess you have tried flashing the bootloader too? And how about using the "flash-all.bat" in the factory images package?

Edit:

Maybe sideloading the zip from the images package that contains boot, system and recovery?

I'm pretty sure that I've tried flashing the bootloader. When I try again (using adb sideload) I get the same signature verification failed message on the N7 that I did when attempting to sideload recovery images. I then get failed to mount cache messages.

I tried the flash-all.bat. Unfortunately that requires fastboot mode and the tablet won't go into fastboot mode. The batch file just sits waiting for the device to respond. Manually typing fastboot devices fails to list anything.

The only "response" that I seem to be able to get is when I put the tablet into sideload mode. I can type adb devices from a command prompt and get a reply with the serial number. The only other adb command that responds is adb sideload - which always reports signature failed on the tablet. Do you think this is a hardware issue?
 

Remcotjuuh

Senior Member
Aug 7, 2012
399
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Groningen, the Netherlands
I'm pretty sure that I've tried flashing the bootloader. When I try again (using adb sideload) I get the same signature verification failed message on the N7 that I did when attempting to sideload recovery images. I then get failed to mount cache messages.

I tried the flash-all.bat. Unfortunately that requires fastboot mode and the tablet won't go into fastboot mode. The batch file just sits waiting for the device to respond. Manually typing fastboot devices fails to list anything.

The only "response" that I seem to be able to get is when I put the tablet into sideload mode. I can type adb devices from a command prompt and get a reply with the serial number. The only other adb command that responds is adb sideload - which always reports signature failed on the tablet. Do you think this is a hardware issue?

I have no idea whether this is a hardware issue, could be, could not be. I remember a thread in which someone had a similar problem, only he had only access to fastboot mode. He eventually fixed it by running the flash-all.bat dozens of times, very strange. So how about sideloading the zip containing boot, recovery and system? I haven't read you tried that. And how about adb pushing flashable zip to your device and flash them in recovery? You can try all kinds of zip, ROMs, recoveries. They do need to be signed because you only have access to the stock recovery I guess.
 
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awhite2600

Member
Jun 28, 2012
15
3
London
I have no idea whether this is a hardware issue, could be, could not be. I remember a thread in which someone had a similar problem, only he had only access to fastboot mode. He eventually fixed it by running the flash-all.bat dozens of times, very strange. So how about sideloading the zip containing boot, recovery and system? I haven't read you tried that. And how about adb pushing flashable zip to your device and flash them in recovery? You can try all kinds of zip, ROMs, recoveries. They do need to be signed because you only have access to the stock recovery I guess.

I've tried sideloading the full factory image. That contains all of the boot, recovery and system images. Just like every other sideload that I've tried the file transfers from the PC. The tablet then reports that the signature verification fails. I've downloaded the factory image three times. I've done FC (file compare) from a command prompt and confirmed that none of the downloads are corrupt - they all match each other.

EDIT: I can't push a flashable zip as I can only adb sideload. I can't adb to just transfer a file. I also can't get into the recovery menu so I can't select a file to flash.

I agree that this is very strange. I've tried Googling the various "can't open / mount cache" message that I keep getting. I can't find anything about them. So this may be a very uncommon issue.

I appreciate your help. I'll keep trying different things. If anyone can think of anything else to try I would appreciate any advice. :fingers-crossed:
 
Last edited:

Remcotjuuh

Senior Member
Aug 7, 2012
399
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Groningen, the Netherlands
I've tried sideloading the full factory image. That contains all of the boot, recovery and system images. Just like every other sideload that I've tried the file transfers from the PC. The tablet then reports that the signature verification fails. I've downloaded the factory image three times. I've done FC (file compare) from a command prompt and confirmed that none of the downloads are corrupt - they all match each other.

EDIT: I can't push a flashable zip as I can only adb sideload. I can't adb to just transfer a file. I also can't get into the recovery menu so I can't select a file to flash.

I agree that this is very strange. I've tried Googling the various "can't open / mount cache" message that I keep getting. I can't find anything about them. So this may be a very uncommon issue.

I appreciate your help. I'll keep trying different things. If anyone can think of anything else to try I would appreciate any advice. :fingers-crossed:

No problem. Just be persistent and try sideloading, and maybe adb pushing, the different kinds of images/.zips. Maybe you'll be lucky and magically succeed just like the other guy did. I guess this is everything I could advise you. Good luck.
 

AndDiSa

Senior Member
Dec 2, 2009
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Fastboot is working only when you are in bootloader mode, when you are in recovery or in "normal" operating mode only adb will work. The command is normally located in the sdk/platform-tools directory of the sdk and I suppose you have the latest android SDK installed.
Btw. for me it makes absolutely no sense that the tablet is booting to recovery directly, because the bootloader is loaded and started before, Only from there you are able to go to recovery, i.e. if recovery mode is working, bootloader must work, too.
To recover your system: go to bootloader mode and get fastboot running, then get the system image and extract all files and do the following:

fastboot flash boot boot.img
fastboot flash recovery recovery.img
fastboot erase system -w
fastboot flash system system.img

fastboot reboot

this should be sufficient. If you want to be sure you can also do

fastboot reboot recovery

and do a system wipe from there. And after that reboot into your system. Good luck!
@Remcotjuuh: it's better to use fastboot instead of adb, because you are one level below, i.e. if your recovery is not working correctly, adb will fail while fastboot does not depend on a working adb process.
 

Remcotjuuh

Senior Member
Aug 7, 2012
399
60
25
Groningen, the Netherlands
and do a system wipe from there. And after that reboot into your system. Good luck!
@Remcotjuuh: it's better to use fastboot instead of adb, because you are one level below, i.e. if your recovery is not working correctly, adb will fail while fastboot does not depend on a working adb process.

I know, but he has clearly said multiple times that he cannot access the bootloader, although I find this very strange too...
 

sakif.kamali

New member
Aug 17, 2013
3
0
Sony xperia s bricked

So you can still access the recovery menu? That surely means that your tablet isn't bricked and if you can access the recovery, then you too must be able to access the bootloader. Power off your tablet and try to boot into fastboot by using power and volume -, volume + isn't necessary. Are you sure you have also installed the drivers for fastboot mode? Then try to flash the factory images using the guide here

http://forum.xda-developers.com/showthread.php?t=1907796

Sent from my Nexus 7 using xda app-developers app

i'm experiencing a similar problem with my phone. i rooted my phone today (using http://forum.xda-developers.com/showthread.php?t=2327473) and it was running fine, but i installed an application from the play store called [Root] Developer tools to allow me to load up recovery boot. i gave it permission but when i tried turning my phone on it just stays blank. ive tried the hard reset (up+power button) but all that happens is my phone vibrates 3 times and a green light flashes. please help
 

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    Fastboot is working only when you are in bootloader mode, when you are in recovery or in "normal" operating mode only adb will work. The command is normally located in the sdk/platform-tools directory of the sdk and I suppose you have the latest android SDK installed.
    Btw. for me it makes absolutely no sense that the tablet is booting to recovery directly, because the bootloader is loaded and started before, Only from there you are able to go to recovery, i.e. if recovery mode is working, bootloader must work, too.
    To recover your system: go to bootloader mode and get fastboot running, then get the system image and extract all files and do the following:

    fastboot flash boot boot.img
    fastboot flash recovery recovery.img
    fastboot erase system -w
    fastboot flash system system.img

    fastboot reboot

    this should be sufficient. If you want to be sure you can also do

    fastboot reboot recovery

    and do a system wipe from there. And after that reboot into your system. Good luck!
    @Remcotjuuh: it's better to use fastboot instead of adb, because you are one level below, i.e. if your recovery is not working correctly, adb will fail while fastboot does not depend on a working adb process.
    3
    sir this saved my n7 how can i donate to you

    I sent them $200 Thursday and I'll send more on my next paycheck

    Sent from my Nexus 7 using xda app-developers app
    2
    I think I may have my Nexus 7 (2012) in a badly bricked state.

    I was running Android 4.3, unlocked and rooted with stock recovery. The tablet froze while using GMail. Pressing the home or back buttons just gave me a black screen with the buttons "highlighted" by circles. I waited several minutes and decided to just power off the tablet. When I looked over about a half hour later I saw that the tablet was frozen on the white Google screen. Two more reboots produced the same result.

    I did some research and determined that it might be a good idea to try a cache wipe. I booted into the bootloader and selected Recovery. The tablet rebooted to an android on his back with a red triangle and the words "No command" underneath. Attempting to boot back into the bootloader (Power, Vol+, Vol-) produced the same results - red triangle and the words "No command". I could no longer boot into the bootloader. Powering off and powering on normally also takes me to "No command".

    I discovered that I can press Power & Vol+ while in the "No command" state. Doing so produces the following text at the bottom of the screen:

    E:Can't open /cache/recovery/log
    E: Can't open /cache/recovery/last_log
    E: Can't open /cache/recovery/last_install
    E: failed closing /dev/block/platform/sdhci-tegra.3/by-name/MSC
    (I/O error)


    I get a menu at the top with the options to reboot, apply update from ADB, wipe data/factory reset and wipe cache. Attempting to wipe cache produces:

    -- Wiping cache...
    Formatting /cache..
    Cache wipe complete.
    E:failed to mount /cache (Invalid argument)
    E:Can't mount /cache/recovery/last_locale


    After a few minutes I boot back to the red triangle android.

    Attempting a factory reset produces:

    --Wiping data...
    Formating /data...
    Formatting /cache...
    Date wipe complete.
    E:failed to mount /cache (Invalid argument)
    E:can't mount /cache/recovery/log
    E:Can't open /cache/recovery/log
    E:failed to mount /cache (Invalid argument)
    E:can't mount /cache/recovery/last_log
    E:Can't open /cache/recovery/last_log
    E:failed to mount /cache (Invalid argument)
    E:can't mount /cache/recovery/last_install
    E:Can't open /cache/recovery/last_install
    E:failed to mount /cache (Invalid argument)
    E: failed closing /dev/block/platform/sdhci-tegra.3/by-name/MSC
    (I/O error)
    E:failed to mount /cache (Invalid argument)


    I've tried using the apply update from ADB option. I can use adb devices to see the serial number. Fastboot doesn't seem to respond and won't list the device. Flashing the factory 4.3 image (downloaded from Google and unzipped) using adb sideload uploads the image and then produces the error:

    Finding update package...
    Opening update package...
    Verifying update package...
    E:signature verification failed
    Installation aborted.

    ...followed by all of the "cache mount / open errors shown previously"

    Not sure what else to try. (I'm learning all of this as I go from reading posts on this site.) Is there a way to adb sideload the recovery partition as I suspect that it is corrupt?

    Sorry to be so long winded. I figured that too much info was better than not enough. Any help would be greatly appreciated.
    2
    You are welcome. I don't need a donation, remember the poor people on the Philippines, just in case.

    Sent from my Nexus 7 using xda app-developers app
    1
    So you can still access the recovery menu? That surely means that your tablet isn't bricked and if you can access the recovery, then you too must be able to access the bootloader. Power off your tablet and try to boot into fastboot by using power and volume -, volume + isn't necessary. Are you sure you have also installed the drivers for fastboot mode? Then try to flash the factory images using the guide here

    http://forum.xda-developers.com/showthread.php?t=1907796

    Sent from my Nexus 7 using xda app-developers app