[GUIDE] Nexus 7 - Factory Image Restore

[Nate Reynolds1]

Thank you so much for this easy tutorial. I was at my wits end trying to get my nexus 7 to update to 4.4. this worked like a charm.

 

[Grant Ziebell]

HELP please!! Attempted factory image restore to 4.3 following instructions given here. Entered the CMD

fastboot flash bootloader bootloader-grouper-4.23.img and received the following

writing bootloader..
FAILED <remote:<invalid state>

also got "Signature Mismatch" in red in the upper left corner of Nexus 7 screen


What to do now??

Thanks

 

[GedBlake]

HELP please!! Attempted factory image restore to 4.3 following instructions given here. Entered the CMD

fastboot flash bootloader bootloader-grouper-4.23.img and received the following

writing bootloader..
FAILED <remote:<invalid state>

also got "Signature Mismatch" in red in the upper left corner of Nexus 7 screen


What to do now??

Thanks

Hi, Grant Ziebell...

Yes. There are known problems fastboot flashing **some** versions of the v4.23 bootloader... and that result in the error message you quote.

This came to light some months ago, in this XDA thread, here...

[Q] JWR66Y nakasi factory image bootloader problem - xda-developers

Also, in this thread, somebody has uploaded the v4.23 bootloader from build JWR66V which has the correct MD5 checksum and is identical to the version I use (and have successfully fastboot flashed).

Here are the links....

v4.23 bootloader from build JWR66V - for WiFi only Nexus 7.
xda-developers - View Single Post - [Q] JWR66Y nakasi factory image bootloader problem

v4.23 bootloader from build JWR66V - for WiFi & 3G (mobile) Nexus 7.
xda-developers - View Single Post - [Q] JWR66Y nakasi factory image bootloader problem.


Both of these appear to be identical and both have the correct MD5 signature for a v4.23 bootloader.

*** A valid 4.23 bootloader ".img" file has an MD5 signature of df53028033c9eccf4fe5ba7bc198ce24 ***

Finally... and before you do anything... you should read the following...

[WARNING][URGENT] N7 grouper (2012 WiFi) bootloader .img files from Google

Flashing a corrupt or incorrect bootloader has the potential for hardbricking the device, so it's absolutely critical you are flashing the correct bootloader for the specfic kind of Nexus 7 you have, and ensure it has the correct MD5 checksum as detailed above.

Hope this helps... and good luck.

Rgrds,
Ged.

 

[Gavin7695]

Hi there,
I'm having some real trouble here but your guide is great!
When I try to flash the .zip image, the process fails on writing system. So I tried what you suggested earlier about flashing each of the .img files separately. Now recovery and boot both flash successfully. But when I try to system.img or userdata.img, my tablet immediately become completely unresponsive.
On the first attempt, I get error 'FileWriteFailed' and if I try it again I get 'InvalidArgument'. I can turn the tablet off and boot into fastboot but the same thing happens again.
A few more details:
I am trying this because the tablet would only get as far as the Google logo when switching on.
In the week before this happened, the tablet would randomly turn off. This didn't happen in Safe Mode but I couldn't locate the source of the issue.

I know you're busy helping so I'd be very thankful for any ideas you might have! Thanks!

 

[Ben Ayres]

Hi there fastboot flash bootloader bootloader-grouper-4.23.img, Failed, (Remote: (InvaildState).Finished..... Please can you tell me why and how to fix this?

 

[GedBlake]

Hi there fastboot flash bootloader bootloader-grouper-4.23.img, Failed, (Remote: (InvaildState).Finished..... Please can you tell me why and how to fix this?

Hi, Ben Ayres...

A couple of posts back in this thread, and in answer to a similar question to yours, I have explained in some detail the likely cause of the <Remote: <InvaildState> error message.

It appears that the v4.23 bootloader that ships with some factory images of Android is either corrupt or in some other way incorrect. This issue has been discussed at length over on XDA, and copies of the v4.23 bootloader that are known to fastboot flash without error have been uploaded and made available... for which, see the links in my previous post.

Hope this helps.

Rgrds,
Ged.

 

[Louis6507]

Hello Ged.
I think I understand everything you are saying but I have a few questions before I continue.

I have a Nexus 7 2012 HSPA. I was running 4.2.2 and was attempting to flash stock + unroot with WUG to 4.4.2 It failed to flash bootloader 4.23 and failed with the error that my bootloader is 4.18. I am stuck on the bootloader now and it does still show that I have Tilapia with bootloader version 4.18.

I have downloaded the file from the link you shared for 4.23 from JWR66V for WiFi and 3G. So now, should I just copy and paste it to C:\Program Files\WugFresh Development\data\Factory_Images\nakasig-kot49h-factory-83d93b5f and then attempt to flash stock + unroot again?

Also, I am unsure how to verify MD5 Signature. But, if I downloaded it from the xda link you provided, it should be good, right?

Thank you,
Louis

 

[Louis6507]

UPDATE: So, I decided to play the lottery since I'll need to be going to bed soon to wake up on time for work tomorrow. THANK YOU Ged.!!!! I used the 3G version of the bootloader by simply replacing the img file that I got in KOT49H from Google. WUG's NRT worked like a champ and everything worked perfectly with the Flash + Unroot. Now I have KiKat.

If anyone wants to update to 4.2.2 and has the bootloader fail and remain on 4.18....Just swap the files like I did in my post and Flash Recovery +Unroot with WUGs and it will upgrade your bootloader to 4.23 and work perfectly. ^_^

Restoring my backups now.

 

[jaymcgill]

The instructions dont say to do this, but you need to run fastbootloader oem unlock. At the end of the instructions it tells you to run fastbootloader oem lock to lock it back. Just FYI, havent read all of the post so someone may have already mentioned this. I have used this to un-brick both of my kids' tablets and it works great.

 

[banz6083]

Hi friend,
Your instructions are very good for someone that has a rough idea about fastboot files etc....however I don't....would you be able to post me something a little more ***** friendly so I can get my nexus 7 out of oblivion?
I appreciate any help I can get as right now my nexus is royally f***ked.

thanks man

Banz

 

[Syahiid Tan]

when i did a fastboot -w update image-razor-kot49h.zip in the command prompt it showed fastboot.exe has stop working.
what should i do

 

[mzanette]

Have a friend's Nexus 7 (2012 wifi) that I can't get into bootloader. When I connect to Windows and try volume down+power I get nothing. The tablet shows up in windows device manager as "APX". I've read in other forums that this means it's hard bricked and I'm SOL. I've previously flashed Nexus 7 and Nexus 5 using fastboot so I know the steps, but I can't get this tablet into fastboot mode. Is it beyond repair?

 

[vash1984]

Looks like my device died Can it be recovered at all now?
Following commands were run:

MacBook-Pro-:Android $ fastboot devices
015d188469500803	fastboot
MacBook-Pro-:Android $ fastboot erase boot
erasing 'boot'...
OKAY [  0.284s]
finished. total time: 0.284s
MacBook-Pro-:Android $ fastboot erase cache
erasing 'cache'...
OKAY [  0.770s]
finished. total time: 0.770s
MacBook-Pro-:Android $ fastboot erase recovery
erasing 'recovery'...
OKAY [  0.597s]
finished. total time: 0.597s
MacBook-Pro-:Android $ fastboot erase system
erasing 'system'...
OKAY [  0.952s]
finished. total time: 0.952s
MacBook-Pro-:Android $ fastboot erase userdata
erasing 'userdata'...
OKAY [  6.998s]
finished. total time: 6.998s
MacBook-Pro-:Android $ fastboot flash bootloader bootloader-grouper-4.23.img
sending 'bootloader' (2100 KB)...
OKAY [  0.278s]
writing 'bootloader'...
FAILED (remote: (Unknown error code))
finished. total time: 34.974s
MacBook-Pro-:Android $ fastboot devices
????????????	fastboot
MacBook-Pro-:Android $ fastboot devices
MacBook-Pro-:Android $ fastboot devices
MacBook-Pro-:Android $

 

[mzanette]

Looks like my device died Can it be recovered at all now?
Following commands were run:

MacBook-Pro-:Android $ fastboot devices
015d188469500803	fastboot
MacBook-Pro-:Android $ fastboot erase boot
erasing 'boot'...
OKAY [  0.284s]
finished. total time: 0.284s
MacBook-Pro-:Android $ fastboot erase cache
erasing 'cache'...
OKAY [  0.770s]
finished. total time: 0.770s
MacBook-Pro-:Android $ fastboot erase recovery
erasing 'recovery'...
OKAY [  0.597s]
finished. total time: 0.597s
MacBook-Pro-:Android $ fastboot erase system
erasing 'system'...
OKAY [  0.952s]
finished. total time: 0.952s
MacBook-Pro-:Android $ fastboot erase userdata
erasing 'userdata'...
OKAY [  6.998s]
finished. total time: 6.998s
MacBook-Pro-:Android $ fastboot flash bootloader bootloader-grouper-4.23.img
sending 'bootloader' (2100 KB)...
OKAY [  0.278s]
writing 'bootloader'...
FAILED (remote: (Unknown error code))
finished. total time: 34.974s
MacBook-Pro-:Android $ fastboot devices
????????????	fastboot
MacBook-Pro-:Android $ fastboot devices
MacBook-Pro-:Android $ fastboot devices
MacBook-Pro-:Android $

You had an error while flashing the bootloader, same thing happened to me. Apparently there was a bug in the bootloader, there's another one out there that is fixed and won't cause the problem. Anyway, since you now have a corrupt bootloader you're done. The tablet is now in "APX" mode and can't be placed into fastboot. Only option is to send back to Google/Asus, unless some genius out there knows how to do a low-level flash with APX tools.

 

[Larry Griffin1]

I have a Nexus 7 Mobile 2nd Gen. I tried to install dual boot. What I ended up with was a boot loop with the four colored spheres. When apt-get, and ADB wouldn't work I found this articule, I followed the article, till error sig images not found. I then manually installed the boot, system, and recovery images. Now I get to the Google screen and it hangs. The error msg I get at the end of the fastboot update, Device product is 'deb',
Update requires 'grouper'. I don't know how the deb got there.

Larry

larry@larry-HP-2000:~/Nexus/ROM/Mobile$ fastboot -w update image-nakasi-kot49h.zip
archive does not contain 'boot.sig'
archive does not contain 'recovery.sig'
archive does not contain 'system.sig'
--------------------------------------------
Bootloader Version...: FLO-04.02
Baseband Version.....: DEB-
Serial Number........: 0a08afd7
--------------------------------------------
checking product...
FAILED

Device product is 'deb'.
Update requires 'grouper'.

finished. total time: 0.017s

 

[Larry Griffin1]

Found the problem wrong files. The files were for the WIFI, grouper, not for Mobile deb.

 

[ShakeSpee]

I'm having trouble unlocking the bootloader now. When I do the "fastboot oem unlock," command, the screen pops up, but when I press yes, it says unlocking now, stays at that screen, and on the cmd window, it says:
<bootloader> unlocking...
FAILED <remote: <unknown error code>>

With the bootloader locked, I can't do anything. Any solutions?

This is in the bottom left corner:
FASTBOOT MODE
PRODUCT NAME - grouper
VARIANT- grouper
MW VERSION - ER3
BOOTLOADER VERSION - 4.23
BASEBAND VERSION - N/A
SERIAL NUMBER - 015d25689a50001d
SIGNING - not defined yet
LOCK STATE - LOCKED

 

[streetrcr]

FANTASTIC .. I tried many images, steps and processes... until I saw this post, I was ultimately stuck. Thank you !! Worked like a charm for 4.23 !!!

 

[stryker314]

tnx... I'm back from the dead... its a pretty good instruction.... easy to follow...

 

[amadhatter]

I'm having trouble unlocking the bootloader now. When I do the "fastboot oem unlock," command, the screen pops up, but when I press yes, it says unlocking now, stays at that screen, and on the cmd window, it says:
<bootloader> unlocking...
FAILED <remote: <unknown error code>>

With the bootloader locked, I can't do anything. Any solutions?

This is in the bottom left corner:
FASTBOOT MODE
PRODUCT NAME - grouper
VARIANT- grouper
MW VERSION - ER3
BOOTLOADER VERSION - 4.23
BASEBAND VERSION - N/A
SERIAL NUMBER - 015d25689a50001d
SIGNING - not defined yet
LOCK STATE - LOCKED

I am having the same problem. It has been trying to unlock for the last 30 minutes. Any help appreciated. I have a feeling it is knackered if I can't unlock it. When I start up the tablet I get the Google logo in the middle of the screen and the bootloader green Start button in the top left hand corner. I can move from the Start button to the Power Off to Recovery Mode and Restart Bootloader with the volume buttons but never get past this screen.There is no lock at the bottom of the screen.