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[Q] Nexus 7 (2012) Stuck in Startup Loop?

OP MrTripStack

22nd August 2014, 05:20 AM   |  #1  
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I recently had an issue with my Nexus 7 freezing constantly and I tried to perform a factory reset through the tablet's setting itself instead of the recovery menu now it seems to be stuck in some sort of loop when I try to start it. This tablet is non-rooted and completely stock, btw.

When the tablet turns on, it boots into a screen that shows an Android with a spinning blue cage on his chest, the word "Erasing..." and a bar at the bottom, which isn't actually filling to show any progress and is instead full blue with these lines going through it.

After a few minutes of that, the blue cage thing and the bar stop moving and the tablet freezes, bringing me to a screen with an Android laying on his back with a red exclamation point above his open chest.

When I press Power and Vol+, it brings me to the recovery menu, with this at the bottom:

Also, I don't know if this is important or not, but it says Android system recovery <3e> and KTU84P at the top of the recovery menu.
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 closing dev/block/platform/sdhci-tegra.3/by-name/MSC (I/O error)
E: failed to mount /cache (Invalid argument)

Being that I'm in the recovery menu, I have the option to reboot, apply update from ADB, wipe data/factory reset, and wipe cache partition. Being as it's constantly telling me that it either can't open or can't mount /cache, I thought wiping the cache partition would help, but that also gives me a bunch of fails:
-- Wiping cache...
E: failed to mount /cache (Invalid argument)
Formatting /cache...
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 closing /dev/block/platform/sdhci-tegra.3/by-name/MSC (I/O error)
E: failed to mount /cache (Invalid argument)

After that, I attempted to do a wipe from this menu, which also gave the same errors:
-- Wiping data...
Formatting /data...
E: failed to mount /cache (Invalid argument)
Formatting /cache...
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
Data wipe complete.
Formatting /cache...
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 closing /dev/block/platform/sdhci-tegra.3/by-name/MSC (I/O error)
E: failed to mount /cache (Invalid argument)

After all that jazz and long wall of failure, it brings me back to the recovery menu. Even with all the failing, I thought it did something since it said "Data wipe complete", but now trying to "reboot system now", it brings me to a solid black screen as if the tablet locked up or just turned off. Turning it back on again, it shows the word "Google" before displaying the original screen of the android with the blue spinning cage and the word "Erasing", effectively completing the loop.

My warranty obviously expired ages ago now and I'm hoping somebody here can help.
22nd August 2014, 09:30 PM   |  #2  
OP Junior Member
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Join Date:Joined: Aug 2014
So, update here: I tried to mess with it some more this morning and it seems that it got through the factory reset it was stuck on, but I'm still having issues with constant freezing.

I can get to the "Google" bootup screen and where the colored circles spin around before bringing me to the menus to set up my Wi-Fi and account and all that (like it did when it was first out of the box), but now it continues to freeze while trying to set up these settings.

I managed to input my Wi-Fi password and skip over the rest of the settings in hopes of getting into the system before another freeze and now it gets stuck on a black screen that only shows the "back" arrow at the bottom and the battery and internet indicators at the top right.

Any ideas, guys? I can effectively get into the bootloader now, but attempting to wipe through the recovery menu gives the same errors as before while clearing cache seems to work without issues.

I attempted to use a Nexus Root Toolkit to "Flash Stock + Unroot" with the "Soft-Bricked/Booloop" option selected and everything seemed to work until it got towards the end when the program stops responding.

Now I can't boot into the system at all and I only get a very primitive "bootloader" that says Google (instead of showing the Android) and that's it. I can use the volume keys to browse between "Start", "Restart bootloader", "Recovery mode", and "Power off". Both Start and Recovery mode bring me to the same exact screen while "Restart bootloader" seems to bring me to a complete bootloader, but choosing any of those options brings me right back to the screen without all the info.

I feel like I'm just messing this up more the more I mess with it and I'm not sure what else to try. This Nexus 7 is completely stock, by the way.
22nd August 2014, 10:01 PM   |  #3  
GedBlake's Avatar
Senior Member
Flag Ashton-under-Lyne, Manchester, UK
Thanks Meter: 397
 
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Quote:
Originally Posted by MrTripStack

I recently had an issue with my Nexus 7 freezing constantly and I tried to perform a factory reset through the tablet's setting itself instead of the recovery menu now it seems to be stuck in some sort of loop when I try to start it. This tablet is non-rooted and completely stock, btw.

When the tablet turns on, it boots into a screen that shows an Android with a spinning blue cage on his chest, the word "Erasing..." and a bar at the bottom, which isn't actually filling to show any progress and is instead full blue with these lines going through it.

After a few minutes of that, the blue cage thing and the bar stop moving and the tablet freezes, bringing me to a screen with an Android laying on his back with a red exclamation point above his open chest.

When I press Power and Vol+, it brings me to the recovery menu, with this at the bottom:

Also, I don't know if this is important or not, but it says Android system recovery <3e> and KTU84P at the top of the recovery menu.

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 closing dev/block/platform/sdhci-tegra.3/by-name/MSC (I/O error)
E: failed to mount /cache (Invalid argument)

Being that I'm in the recovery menu, I have the option to reboot, apply update from ADB, wipe data/factory reset, and wipe cache partition. Being as it's constantly telling me that it either can't open or can't mount /cache, I thought wiping the cache partition would help, but that also gives me a bunch of fails:
-- Wiping cache...
E: failed to mount /cache (Invalid argument)
Formatting /cache...
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 closing /dev/block/platform/sdhci-tegra.3/by-name/MSC (I/O error)
E: failed to mount /cache (Invalid argument)

After that, I attempted to do a wipe from this menu, which also gave the same errors:
-- Wiping data...
Formatting /data...
E: failed to mount /cache (Invalid argument)
Formatting /cache...
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
Data wipe complete.
Formatting /cache...
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 closing /dev/block/platform/sdhci-tegra.3/by-name/MSC (I/O error)
E: failed to mount /cache (Invalid argument)

After all that jazz and long wall of failure, it brings me back to the recovery menu. Even with all the failing, I thought it did something since it said "Data wipe complete", but now trying to "reboot system now", it brings me to a solid black screen as if the tablet locked up or just turned off. Turning it back on again, it shows the word "Google" before displaying the original screen of the android with the blue spinning cage and the word "Erasing", effectively completing the loop.

My warranty obviously expired ages ago now and I'm hoping somebody here can help.

Hi, MrTripStack...

Unfortunately, this doesn't sound good at all, I'm afraid...

Your error outputs suggest some kind of partition corruption... and given that your device is running unrooted factory stock (ie, no modifications), I'm inclined to suspect hardware failure with the devices internal eMMC chip. The "failed to mount..." errors are suggestive of this.

The only thing I can suggest, is you attempt to fastboot flash back to factory stock (see download link in my sig. below for the factory image for your specific device).

Full instructions available here...

[GUIDE] Flashing a Factory Image with fastboot / return to stock
(But be aware of a known issue fastboot flashing the v4.23 bootloader that ships with some versions of factory stock; fastboot flashing it causes error messages. Pay particular attention to the comment in red, right at the top, in the very first post in the above link/thread.)

-----------------------------------------------------------------------

I'm not optimistic this will work though... if there is a problem with the eMMC chip, you will likely see a whole raft of similar error messages during the fastboot flash process.

For what it's worth... good luck.

Rgrds,
Ged.

ADDENDUM: Just seen your additional post, which you posted whilst I drafting mine... and it seems to confirm my suspicions that you probably have a hardware problem (eMMC chip).
Last edited by GedBlake; 22nd August 2014 at 10:18 PM.
22nd August 2014, 10:20 PM   |  #4  
OP Junior Member
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Quote:
Originally Posted by GedBlake

ADDENDUM: Just seen your additional post, which you posted whilst I drafting mine... and it seems to confirm my suspicions that you probably have a hardware problem (eMMC chip) .

I was afraid of this, but at least my suspicious are seeming more and more confirmed. Is it worth it (or even possible) to replace the eMMC chip or should I just scrap the tablet entirely?
22nd August 2014, 11:17 PM   |  #5  
GedBlake's Avatar
Senior Member
Flag Ashton-under-Lyne, Manchester, UK
Thanks Meter: 397
 
660 posts
Join Date:Joined: Jan 2013
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Quote:
Originally Posted by MrTripStack

I was afraid of this, but at least my suspicious are seeming more and more confirmed. Is it worth it (or even possible) to replace the eMMC chip or should I just scrap the tablet entirely?

I'm no hardware expert, but I really don't think it's possible to replace the eMMC chip. It's pretty much 'embedded' into the motherboard, and soldered into place by a computer controlled machine, with very fine and very precise spot soldering... way beyond the capability of any human equipped with a soldering iron to attempt.

You could though, consider replacing the motherboard itself, which has been attempted by another XDA member, and apparently, successfully...

http://forum.xda-developers.com/show...&postcount=824

Rgrds,
Ged.
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