yashsingh1/xdaforums huggingface dataset:
[Nexus 7 Q&A, Help & Troubleshooting] globula_neagra:
On the 3g version, same thing :)

C:\Users\Glob>fastboot flash bootloader E:\Nexus\nakasig-jwr66y-factory-bdbb7bd7

\nakasig-jwr66y\bootloader-tilapia-4.23.img

sending 'bootloader' (2100 KB)...

OKAY [ 0.277s]

writing 'bootloader'...

FAILED (remote: (InvalidState))

finished. total time: 0.420s
[Nexus 7 Q&A, Help & Troubleshooting] GedBlake:
This is weird...

I'm not naturally inclined to fastboot flash a bootloader, unless absolutely necessary - even for curiosities sake.

So I decided to take a closer look at the 4.23 bootloader image files themselves... from both build JWR66V and the very latest build, JWR66V... by running some checksum tests on both.

And here's the kicker... they are different... despite having the same name.

I have no idea why this should be, but it probably explains why some are having problems flashing it.

Here are my findings...

bootloader-grouper-4.23.img from JWR66V
---------------------------------------

Size: 2.05 MiB (2,150,992 bytes)

MD5: df53028033c9eccf4fe5ba7bc198ce24

SHA-1: 7b28b45a035efb9aad9e61ad09b1906eb5508721

CRC32: c4eefbd8

bootloader-grouper-4.23.img from JWR66Y
---------------------------------------

Size: 2.05 MiB (2,151,068 bytes)

MD5: 5bdb2e87370cdb1a7ea14bb0c3e21390

SHA-1: ce2951e59da64fa57d281f47031364050c83f49c

CRC32: 7ab6084b

Make of this what you will...

I'm just puzzled! :confused:.

Rgrds,

Ged.
[Nexus 7 Q&A, Help & Troubleshooting] Auth:
Same here. Also after flashing system image and rebooting I get android warning icon on first loading. I had to push button to reboot device. But after all it works ok. So weird. :silly:
[Nexus 7 Q&A, Help & Troubleshooting] GuestK00329:
This is interesting. Is it possible to open or extract the .img files and investigate further what the differences might be?
[Nexus 7 Q&A, Help & Troubleshooting] simics:
confirmed, the BL in 66Y is not working. Keep getting Invalid State on the command prompt and the Nexus screen has red words saying invalid signature.

sending 'bootloader' (2100 KB)...

OKAY [ 0.299s]

writing 'bootloader'...

FAILED (remote: (InvalidState))

finished. total time: 0.438s

Got the "old" 4.23 BL from JWR66V and all is well again.

http://xdaforums.com/showthread.php?t=2150251
[Nexus 7 Q&A, Help & Troubleshooting] glitchsys:
Wow guys, thanks so much. I've been trying to flash the official 4.3 image (JWR66Y) onto my Nexus 7 and I kept getting:

FAILED (remote: (InvalidState))

when it tried to write the bootloader. It would refuse to write the system image after because it detected the boot loader was still the older version, 4.18 or something. After finding this thread I found JWR66V at:

https://dl.google.com/dl/android/aosp/nakasi-jwr66v-factory-d341d356.tgz

Was able to successfully write the 4.23 bootloader from that leaked built, and then I was able to write the JWR66Y image, since it now detected my bootloader was 4.23; It's weird the 4.23 bootloader in JWR66Y is broken but the 4.23 bootloader in JWR66V works just fine.
[Nexus 7 Q&A, Help & Troubleshooting] GedBlake:
Hi, Eregoth...

Unlikely, I'm afraid... bootloader.img files are closed source and nobody knows what they contain except Asus (this is why there is no changelog, detailing the added features of v4.23 over v4.18, for example).

A bootloader is crypto-signed to the unique ID of a given Nexus 7, and when you flash a new one it 'inherits' the previous bootloaders data. The bootloader acts as a kind of security gate keeper and becomes active every time you switch on the Nexus 7. It's a system critical component of the Nexus 7, and without it... nothing happens:(. You can mess up pretty much any partition on the Nexus 7, and still recover from it... and is typically known as a softbrick, and is characterized by such egregious behaviour as bootlooping or refusal to boot... but as long as can you see the White-on-Black Google logo (which is the bootloader) upon boot or the White-on-Black battery charging animation (also the bootloader) when charging from a fully shut down state... as long as you can see these, the device isn't hardbricked and most of the time can be recovered.

If you corrupt, or erase the bootloader... the Nexus 7 is dead, from which there is known recovery. Although it's been speculated that an nvFlash tool could flash a new bootloader. I've used nvFlash before, on another tablet, and it's considerably more flexible/powerful than fastboot (you can change partition sizes, called 'layouts', for example)... but so far, nobody has been able to make nvFlash work on the Nexus 7:(.

This

PDF document

lodged by Nvidia Corporation with the United States Patent office in 2009 gives some indication of a what a bootloader is and what it's purpose is. Although somewhat technical, and a little out of date, it's worth reading.

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

All of which, though interesting, doesn't explain why the two v4.23 bootloaders are different. And reading through the posts here on this thread, it's clear there is a problem.

Fastboot flashing a bootloader is a risky procedure at the best of times, and always makes me nervous. And this kind of thing hardly inspires confidence in me.

Unless I've seriously misunderstood something, or I'm missing something, I think the only logical conclusion I can draw is Google have screwed up the bootloader that ships with Build JWR66Y.

I've just done a Google search on this topic, to see if it's been flagged up anywhere else, outside of XDA... but so far, nothing. But it's early days, and build JWR66Y has only been available for around 24hrs... so who knows what may crop up over the next few days. Unless Google quietly fixes the problem, I suspect many people wishing to restore back to stock 4.3 are going to have similar problems as those who have reported on this thread.

Anyway... I guess we'll see what happens...

Still damned odd, though.

Rgrds,

Ged.
[Nexus 7 Q&A, Help & Troubleshooting] globula_neagra:
An OTA update re-writes the bootloader also, so even if you do it yourself, or leave google to do it, it she same risk :)

Eg: The OTA update from 4.2.2 has corrupted my Radio partition, and now it seems that i am using a backup radio. Still nobody knows which partition is the radio, so i can fix the issue (the fstab.mmc says that the format of the radio partition is ext4, so if someone will do a dd dump i should be able to restore my radio)

Just received the ota 2mb size, strange
[Nexus 7 Q&A, Help & Troubleshooting] _never_mind_:
bootloader-grouper-4.23.img from the jwr66v and image-nakasi-jwr66y.zip ?

Does it work to use the bootloader-grouper-4.23.img from the jwr66v and then flash image-nakasi-jwr66y.zip ??
[Nexus 7 Q&A, Help & Troubleshooting] microphonehead:
So what can I do to get it to work?! Just saying failed every time :(

Hey guys, sorry I didn't read the thread properly the first time, that's what happens when you rush!

Thanks!
[Nexus 7 Q&A, Help & Troubleshooting] relaxxer:
Same here, the 'Y' is not working!
[Nexus 7 Q&A, Help & Troubleshooting] dragon884:
Hi everyone,

Thought i was the only person having this issue. This is how i sorted my problem and i do hope that it'll fix anyone having this issue. This is what i done. Not a proper fix but at least i didn't see any errors.

1. Downloaded the JWR66V version

2. md5 checked it to confirm that it is the legit image file

0f426a1981338b637aa12ff7bbd197be nakasig-jwr66v-factory-aebc7b11.tgz

3. Used mskip's Toolkit to flash (supported on up to 4.2.2 but you can still use the JWR66V image. Just gives a warning message)

4. Confirmed no errors

5. Turned on my Nexus and did a brief setup

6. Nexus 7 picked up the update and i selected to install

7. After install root

8. Factory reset

Step 8 is optional.
[Nexus 7 Q&A, Help & Troubleshooting] Spco:
This explains a lot and you're right. I extracted the bootloader from nakasi-jwr66v-factory-d341d356.tar for those who want the bootloader only and want to flash to the latest build.(nakasi-jwr66y)
[Nexus 7 Q&A, Help & Troubleshooting] legiong:
I was able to fix mine after soft-bricking it by following this guide:

http://forums.androidcentral.com/nexus-4-rooting-roms-hacks/224861-guide-nexus-4-unlock-root.html

Apologies for linking to another forum.

The bootloader from JWR66Y failed like everyone else, so I downloaded the 4.3 JWR66V from the link that glitchsys posted above and used the bootloader from that.

After that I was able to use adb to flash JWR66Y downloaded from google.

JWR66Y:

https://dl.google.com/dl/android/aosp/nakasi-jwr66y-factory-1e503532.tgz
[Nexus 7 Q&A, Help & Troubleshooting] M.Q.:
I know that this is the Wifi version thread, but in case anyone with 3G have the same question - attached is the 4.23 bootloader for N7 3G extracted from JWR66V

After flashing it I was able to successfully flash the JWR66Y system image.
[Nexus 7 Q&A, Help & Troubleshooting] acolin:
Bricked with grouper-4.23 bootloader

Just flashed the bootloader attached to a message in this thread:

MD5: df53028033c9eccf4fe5ba7bc198ce24

Checked md5sum before flashing.

Flashed fine with

$ fastboot flash bootloader bootloader-grouper-4.23.img

The signature matched message showed up on device, fastboot exited on host, then I rebooted the bootloader using menu, and... it rebooted into black screen of death. I believe this is what they call hardbricked from which there is no return ='(

The only thing I did not-by-the-book is to flash it twice, ie. executed the above fastboot command twice (with no reboot in between).

Others doing the same -- mind this accident.

EDIT: *before* flashing this bootloader I ran ./flash-all.sh which does 'fastboot erase boot', but, as my terminal history confirms, I flashed the bootloader after that (and nothing happened between the bootloader flashing and the fatal reboot).

EDIT: it came back to life on its own. The bootloader-version is 4.23, so it did flash successfully. The only explanation I have is that the new bootloader (4.23) does not start if the battery is too low and its threshold is higher than that in the previous version (4.13), if the previous version even had such a threshold at all. Another possibility of the same flavor is that the battery drained while in bootloader: when the (old) bootloader started the first time, the battery check succeeded, then the battery drained but the bootloader kept running (assuming it does not do battery checks while it runs), and finally after flashing and rebooting, upon starting the (new) bootloader, the battery check no longer succeeded, until I charged it up more.

LESSON: Charge your device to full capacity EVEN IF you plan to keep it plugged into USB during the whole operation.
[Nexus 7 Q&A, Help & Troubleshooting] woldranger:
You, kind sir, are a lifesaver! I was stuck on the very last part and it was telling me about the 4.18 bootloader even though the OP of the thread had walked me through it and gave me the ling to the updated bootloader - what he'd forgotten was that I was on the 3G NOT wifi. I tried yours and I'm up and running :D The battery was dropping and I was getting worried - it took me 9 hours to get it back after the botched attempt to unroot it using wug's toolkit.

Thanks again!

Tomorrow I'm gonna have a go at rerooting it....
[Nexus 7 Q&A, Help & Troubleshooting] M.Q.:
You're welcome :) I'm glad I could help.
[Nexus 7 Q&A, Help & Troubleshooting] woldranger:
It's a little strange though, I was told by the OP from my thread who helped me through my problems, that the bootloader image you that I used from your link wasn't for the 3G, but actually the WIFI which happened to be identical - at the end of the day, I'm not fussed either way - it's done and I will be selling the tablet tonight :)
[Nexus 7 Q&A, Help & Troubleshooting] ccjb100:
Hey BIG shoutout and thanks to everyone in this thread. You all saved my butt today. :) I too had the same issue described here.

What happened: I had a friends Nexus 7 that was always failing to update. Attempting to OTA update would always give the Android robot laying down with a red exclamation over it every time. It was still on 4.1.2. Anyhow I took and tried to fix it up. Doing a factory reset and trying again gave same result. Hooked it up to Nexus Root Toolkit and attempted a full factory image load of 4.2.2. That froze/failed trying to send some of img's over to flash. I could still get bootloader but completely borked recovery and would not boot normally. After fiddling with my usb setup I was finally able to unlock the bootloader and then manually reflash stock 4.1.2 recovery. Then I tried again to do a full factory image load of 4.3 (JWR66Y) and immediately failed out of bootloader flash with the "invalid state" error (I was on 4.18 bootloader at the time). At this point I became somewhat concerned. Although I could still boot bootloader it was freezing up sometimes. Anyway, once I found this thread I went back again and tried JWR66V and tried a full load through NRT. Everything loaded perfectly this time (including the 4.23 bootloader from JWR66V) and I booted up normally. I was able to OTA to newest update like normal once I had JWR66V in place.

Thank you so much everyone!
[Nexus 7 Q&A, Help & Troubleshooting] mkrogh65:
Sooo im stuck on bootloader after trying to install nakasi-jwr66y-factory-1e503532

But it says something about missing

boot.sig

Recovery.sig

And Bootloader is 4.18

And Needs to be bootloader 4.28

At this point im stock and need help before I really mess this up

I can boot into bootloader, and not get further than that.

Can I install JWR66V via wugfresh ?

And bee home free?

Mick :)

---------- Post added at 09:36 AM ---------- Previous post was at 09:36 AM ----------

---------- Post added at 10:34 AM ---------- Previous post was at 09:36 AM ----------

Installed this one via Nexus root ToolKit v.1.7.2

JWR66V at:

https://dl.google.com/dl/android/aos...y-d341d356.tgz

Now im back "online", and have bootloader 4.28, and android 4.3

System says there is an update, but I guess ill have to OEM lock my bootloader first. (before updating)

If this helps any1

Mike out.

---------- Post added at 10:45 AM ---------- Previous post was at 10:34 AM ----------

Via Nexus root toolkit.

After OEM lock my bootloader I got Android JWR66Y on my device :)

Tnx myself ;)

Mike
[Nexus 7 Q&A, Help & Troubleshooting] jb0ne:
Wow I didn't even realize how dangerous flashing your bootloader is. I flashed a stock 4.3 JWR66V on, and flashed a 4.23 bootloader, and have since managed to update to OTA JWR66Y. I had no problems, but now I'm wondering which bootloader I have (V or Y), and whether was I just lucky.

How would I check which 4.23 bootloader I have on my device?
[Nexus 7 Q&A, Help & Troubleshooting] tatazeuz:
They're exactly the same bootloader. Theres absolutely no difference between JWR66V and JWR66Y bootloaders.
[Nexus 7 Q&A, Help & Troubleshooting] GedBlake:
Hi, tatazeuz...

You'd certainly expect them to be identical, wouldn't you?... but they aren't. There's actually a 76 byte discrepancy between the two.

My own investigations (as previously reported), yielded the following puzzling results...

bootloader-grouper-4.23.img from JWR66V
---------------------------------------

Size: 2.05 MiB (2,150,992 bytes)

MD5: df53028033c9eccf4fe5ba7bc198ce24

SHA-1: 7b28b45a035efb9aad9e61ad09b1906eb5508721

CRC32: c4eefbd8

bootloader-grouper-4.23.img from JWR66Y
---------------------------------------

Size: 2.05 MiB (2,151,068 bytes)

MD5: 5bdb2e87370cdb1a7ea14bb0c3e21390

SHA-1: ce2951e59da64fa57d281f47031364050c83f49c

CRC32: 7ab6084b

And this causes problems when attempting to fastboot flash the bootloader from build JWR66Y... you get 'signature mismatch' and 'InvalidState' errors:(.

It's a know issue - as well as this thread, it's also referenced in this

sticky

by the OP himself.

But nobody seems to know quite

why

the two bootloaders are different. I've done a bit of Googling around to see if I can find an answer... but so far, I've found nothing.

Probably just one those mysteries that will forever go unanswered:).

Rgrds,

Ged.
[Nexus 7 Q&A, Help & Troubleshooting] tatazeuz:
I was aware of this, although I'm pretty sure that somebody screwed when compiling the package, because if you update vía OTA, the bootloader is exactly the same. And since the guy that I replied to updated via OTA, I said that.
[Nexus 7 Q&A, Help & Troubleshooting] jb0ne:
Really? I thought there was some discussion on this thread earlier about different file sizes and md5s for the 4.23's?
[Nexus 7 Q&A, Help & Troubleshooting] tatazeuz:
The bootloader in the JWR66Y factory image is corrupted, thats why they have different sizes.
[Nexus 7 Q&A, Help & Troubleshooting] jb0ne:
So since mine is working that means I must have put the JWR66V one on? I'd really like to be able to know for sure, but I don't know where the .img file is stored on the device so I can md5 it.

Edit: Eh, I just found the .img file on my hard drive - it's the V one. So I guess I got lucky not going too bleeding edge.

Edit2: Interestingly enough, while the file size is identical to the byte for the V bootloader, the md5 is different! It's

df53028033c9eccf4fe5ba7bc198ce24

I downloaded it from one of the threads here but don't recall which.
[Nexus 7 Q&A, Help & Troubleshooting] ctbaker:
Thanks to everyone that helped in this thread. I just about had a heart attack thinking I just made my daughter's nexus 7 into an expensive brick!
[Nexus 7 Q&A, Help & Troubleshooting] Luxferro:
I also had problems flashing the 4.23 bootloader from googles jwr66y factory images. Thanks for pointing out the previous version of 4.23. It worked fine.

Now I can move on to android 4.4 (kitkat) :)
[Nexus 7 Q&A, Help & Troubleshooting] hanatha:
Life saver for my Nexus 7 wifi

Thanks everyone. Brilliant that someone found out a faulty bootloader - jwr66y.

Just to share my experience.

After flashing the jwr66v bootloader, I failed to update jwr66y zip so I updated with jwr66v zip.

Later after rebooting the machine, I use system update to bring it to jwr66y.
[Nexus 7 Q&A, Help & Troubleshooting] fushla:
Anyone need to restore their bootloader? It seems both bootloaders (4.4 and 4.3) have been replaced (the size is different than previous ones) at the developer page .... Curious if everything works now.. I'm scared to check though :D
[Nexus 7 Q&A, Help & Troubleshooting] sheridanmp:
Thanks, works but...

Thanks to the various people that provided the info to load bootloader 4.23. It worked though I still could not flash JWR66Y as I got the same invalid state happening so tried 4.4 (forgotten the code) and that loaded just fine.

Good enough. I now have:

Product Name - grouper

Variant - grouper

HW Version - ER3

Bootloader version - 4.23

baseband version - n/a

Serial # - long number

Signing - not defined yet

Lock state - unlocked

But the overall response is very slow when using the touch screen etc. Anyone else having this happen?

Thanks again

Sher
[Nexus 7 Q&A, Help & Troubleshooting] bftb0:
Follow-up: SAME ISSUE WITH KOT49H FACTORY IMAGE

FYI, this same problem also exists with the bootloader image file shipped in the newer KOT49H Google "Factory Image". Thought I would mention it here in case anyone reads through this thread.

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

The bottom line (at the moment) is that the correct version of the bootloader file (for flashing with fastboot or nvflash) "bootloader-grouper-4.23.img" is:

2,150,992 bytes long. MD5: df53028033c9eccf4fe5ba7bc198ce24

and is present in the JWR66V, KRT16O, and KRT16S factory images.

The file of the same name which are derived from the JWR66Y and KOT49H Google factory images should be avoided.
[Nexus 7 Q&A, Help & Troubleshooting] malibu_23:
This is likely why i cant flash 4.4.2 on my n7 2012 wifi. So what do i do? swap th bootlaoder from krt16s?
[Nexus 7 Q&A, Help & Troubleshooting] bftb0:
Sure. Or if you are already on the 4.23 bootloader, there is no need to flash it again.
[Nexus 7 Q&A, Help & Troubleshooting] sportscrazed2:
So I replaced the bootloader file downloaded directly from google with the one provided in op and everything worked right away the way it was supposed too. Does nobody at google test this **** anymore?
[Nexus 7 Q&A, Help & Troubleshooting] MTodd88:
Cannot boot

So the 2nd time I fired up my Nexus 7 it proceeds to tell me that I need to update some files. I tell it to go ahead and now it will not boot up. I get the Google start page and then the "X" logo flashing but that is it. I have read a bunch of stuff around about how to fix the problem but I cannot get any of them to work. I can get to the Recovery page and to the Bootloader page but nothing happens from there. I have tried to wipe the data and no luck. I have tried to use WugFresh's root toolkit but this isnt working either because I apparently do not have USB Debugging enabled and I cannot get the device to boot up in order to enable that option.

Any help would be appreciated.
[Nexus 7 Q&A, Help & Troubleshooting] Erovia:
Is your N7 customized in any way (recovery,rom,etc) or full stock?
[Nexus 7 Q&A, Help & Troubleshooting] jb0ne:
Download the factory image fort your nexus 7 from Google. Decompress it and you'll get about 7 files. One is a batch file that will use fastboot to wipe your system and update your OS. If you're savvy enough you can run the fastboot commands yourself and not wipe your data. Just don't "fastboot flash data userdata.IMG"

Edit: don't flash recovery either if you like your custom recovery. Just boot, system, and I would do bootloader (and did and have) but you may get advice from others not to.
[Nexus 7 Q&A, Help & Troubleshooting] MTodd88:
I was actually able to get it to work finally. Not sure exactly how I did it but I was finally able to get it to boot far enough so that I could change the USB setting on the device and I finally got it to recognize the ADB setting.
[Nexus 7 Q&A, Help & Troubleshooting] motorbreath1:
I am a very green noob. What program must I use to get this fixed? How do you use the new 4.23 file to make the mismatched signature problem get resolved? Thank you in advance.
[Nexus 7 Q&A, Help & Troubleshooting] motorbreath1:
I'm desperate!!

Ok, Something incredibly wrong has occurred with my bootlooped 2012 Nexus 7. I was experiencing the problem in the OP. The signature mismatch problem that has plagued so many. I tried several times to use Wugfresh's Nexus Root Toolkit to no avail. It got to where it would not recognize adb when trying to install the drivers needed. Then, the other shoe dropped. I left the N7 plugged into my PC while in fastboot mode for a couple hours while I took a break to deal with some other things. This was a catastrophic move, because when I returned to the PC, the screen was flickering with green and black bars. I quickly unplugged my device, it shut off, and I have not been able to get it to boot into fastboot or even into the Google screen. I think I officially bricked it. :eek: Does any master out there have an idea of what I've done? Thank you in advance.
[Nexus 7 Q&A, Help & Troubleshooting] Erovia:
If you can't boot into fastboot, return it to Asus (or Google). They are the only ones who can repair it. Sorry.
[Nexus 7 Q&A, Help & Troubleshooting] motorbreath1:
Thank you. I believe I got it to come back to life, but now I am back to square one with my original problem. When the bootloop happened I tried to using Wugfresh NRT to restore factory images. I got the mismatched signature problem. And then it wouldn't recognize adb for my to install the proper drivers. I downloaded the bootloader-grouper-4.23.img file from this post, but am not sure what to do next. I apologize for my utter ignorance. Any guidance or advice would be greatly appreciated. Much thanks.
[Nexus 7 Q&A, Help & Troubleshooting] Erovia:
Try the latest official image (4.4.2): https://developers.google.com/android/nexus/images#nakasi