Flatline - Unbrickable Nexus 7 (Wi-Fi + 3G) - Nexus 7 Original Development

The AndroidRoot.Mobi Team is proud to present Flatline: Nvflash for Nexus 7 & Nexus 7 3G (2012)
This release allows generating nvflash blobs for your specific device, making your device unbrickable as long as you have a copy of the blobs.
As a brand new feature, it will also enable wifi and upload a copy of the blob to androidroot's server. Later, a solution will be released to retrieve the blobs from the server if you ever loose them.
https://www.androidroot.mobi/pages/guides/tegra3-guide-nvflash-jellybean/
Credit goes to the AndroidRoot.Mobi team:
Bumble-Bee (Apache14), IEF, kmdm, lilstevie & RaYmAn.

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BrianXP7 said:
Ah yes! This makes updating the bootloader a less scary procedure. (It happened to me and I had to send an RMA request. Fortunately, they accepted it.) I do have a question. Are the blobs hardware specific for the Nexus 7? (Flashing someone's Nexus 7 dump to mine.)
Sent from my Nexus 7 using xda app-developers app
Click to expand...
Click to collapse
The blobs are device-specific. They will only works on your particular device and no one elses.
Otherwise, we would have just released pre-made blobs

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Hi! I have tried to nvflash my TF300T with the new guide, but after generating the blob.bin and run whille I am getting an error:
Code:
Wheelie 0.1 - Preflight for nvflash.
Copyright (c) 2011-2012 androidroot.mobi
========================================
Waiting for device in APX mode...
[=] Chip UID: 0x15d2d4228340213
[-] Incorrect BLOB selected. nverror: 0x4.
Seems like the bootloader didn't flash the first time - after the second try and regenerating the nvflash files it works.

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so the guide on androidroots website should be followed before you start tinkering with your device? just wondering. I have an N7, but have never messed it up to the point where fastbooting the factory image doesn't work. only killed it due to a hardware error

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Can you still use this if you can only access the APX mode due to a bricked tablet?

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BrianXP7 said:
[/COLOR]I successfully backed up the blobs and partition images. I'm happy someone finally found a unbrickable solution. However, I tried flashing back the stock bootloader (4.23) but it displayed "Signature mismatch." in red on the top left corner and failed. (Luckily, I can still interactive with the bootloader menu.) Would flashing a ZIP with the image inside work as a workaround? Is there a special procedure that I have to perform? Are you going to release a modified 4.23 bootloader?
Click to expand...
Click to collapse
Try flashing the bootloader with nvflash rather than fastboot, flashing the bootloader from fastboot and recovery is subject to a signature check.

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BrianXP7 said:
Wouldn't that flash the modified bootloader? Also, I can't find instructions on flashing the bootloader under NVFlash.
Click to expand...
Click to collapse
if you have any bootloader you can flash it with nvflash easily. nvflash -r --download 4 bootloader.bin and it will flash, this isn't just limited to the stock bootloaders either, you can use this to attempt porting other bootloaders like u-boot.

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BrianXP7 said:
I ran out of thanks... Thanks...
Edit: So I rename "bootloader-grouper-4.23.img" from the factory image archive to "bootloader.bin" or is it something else entirely? Just double checking before I screw any partitions...again.
Click to expand...
Click to collapse
doesn't matter what it is called I just used bootloader.bin as an example
Code:
nvflash -r --download 4 $filename
is probably the most appropriate way to represent it where $filename is whatever you called the bootloader

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Does this mean with this we would be able to make a bootloader with custom splash screens??
Sent from my Nexus 7 using Tapatalk 4

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heavy_metal_man said:
Does this mean with this we would be able to make a bootloader with custom splash screens??
Sent from my Nexus 7 using Tapatalk 4
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Click to collapse
if you wanted you could try yes. not too sure about the format the current splash is though

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lilstevie said:
if you wanted you could try yes. not too sure about the format the current splash is though
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Click to collapse
Hmmm. This is great work do you know if anyone on any of the other Asus devices have succeeded in changing the splash screen? That may be a good place to start looking. I shall look into this
Sent from my Nexus 7 using Tapatalk 4

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BrianXP7 said:
I risked and I screwed up. It's not recognised anymore... Any other suggestions? I hate having to send another RMA request...
Click to expand...
Click to collapse
you should be able to still hit APX as that is not controlled by the bootloader

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heavy_metal_man said:
Hmmm. This is great work do you know if anyone on any of the other Asus devices have succeeded in changing the splash screen? That may be a good place to start looking. I shall look into this
Sent from my Nexus 7 using Tapatalk 4
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Click to collapse
Nope, but afaik it is a standard format across tegra devices, so maybe look up other tegra based devices as a starting point

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lilstevie said:
Nope, but afaik it is a standard format across tegra devices, so maybe look up other tegra based devices as a starting point
Click to expand...
Click to collapse
OK cool, any ideas on where I can get a start on decompiling the bootloader to have a look at its internals?
Sent from my Nexus 7 using Tapatalk 4

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BrianXP7 said:
This is probably going to annoy you a lot. I tried holding the power button for more than 30 seconds and doing weird button combinations but it still wouldn't get recognized. Should I try draining the battery? (I have a feeling it might take quite some time...)
Click to expand...
Click to collapse
I'm one of the only androidroot members who doesn't own an N7 so I will have to defer to one of the others for where to go, but I do believe one of them has ended up in a similar situation but managed to get out of it.
heavy_metal_man said:
OK cool, any ideas on where I can get a start on decompiling the bootloader to have a look at its internals?
Sent from my Nexus 7 using Tapatalk 4
Click to expand...
Click to collapse
IDA would be the best place to start

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I know how to install the 4.23 bootloader...
Step 1: Get into fastboot by... Well if you don't know how to get into fastboot then why did you do this???
Step 2: Get the unmodified 4.13 bootloader (attached as 413bl.img ) and flash it by using" fastboot flash bootloader 413bl.IMG"
Step 3: Reboot into bootloader using volume keys
Step 4: Flash the 4.23 bootloader (attached as bootloader-grouper-4.23.img )
Step 5: Reboot
Step 6: ???
Step 7: Profit

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Remove the battery and try again...
BrianXP7 said:
Alright, thanks. I'll keep updated on this topic for the solution.
I became way too courageous... I actually need my tablet for school so please find it soon. (No pressure. )
Click to expand...
Click to collapse
Pop off the back cover using a guitar pick or fingernails and remove the battery cable and try to get into NVflash. If you don't know how to unplug the battery go onto ifixit and search for N7 disassembly

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BrianXP7 said:
Alright, thanks. I'll keep updated on this topic for the solution.
I became way too courageous... I actually need my tablet for school so please find it soon. (No pressure. )
Click to expand...
Click to collapse
Code:
18:10 <@RaYmAn> you have to hold down uhm, all buttons or something for like 10 seconds, while it's plugged in
18:10 <@RaYmAn> and then you have to let go of power and voldown at *just* the right time
but make sure you charge the battery for a bit first with the charger in case the battery is starting to run low

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lkspooky said:
Step 1: Get into fastboot by... Well if you don't know how to get into fastboot then why did you do this???
Step 2: Get the unmodified 4.13 bootloader (attached as 413bl.img ) and flash it by using" fastboot flash bootloader 413bl.IMG"
Step 3: Reboot into bootloader using volume keys
Step 4: Flash the 4.23 bootloader (attached as bootloader-grouper-4.23.img )
Step 5: Reboot
Step 6: ???
Step 7: Profit
Click to expand...
Click to collapse
Is this after you have generated blobs with the modified bootloader ?
i.e. after you have generated your blobs with the androidroot.mobi bootloader you flash standard 4.13 b/l and then afterwards 4.23 ?

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Post blob generation
wildestpixel said:
Is this after you have generated blobs with the modified bootloader ?
i.e. after you have generated your blobs with the androidroot.mobi bootloader you flash standard 4.13 b/l and then afterwards 4.23 ?
Click to expand...
Click to collapse
This is after you generate blobs