[Nvidia Tegra Note 7] hacktrix2006:
This is my first APX recovery android device its a bit different from flashing my desire HD or HTC. Wildfire thats for sure what I have learnt so far is based on Tegra 2 and 3 as 4 and 4i are new not much is known about it. It was the same with the nexus 7 2012 edition which was a Tegra 3 but the key was found in the end. Problem is if the SBK is device unique like it was with the other the ones that are bricked might struggle. Let's just hope there is a brand master key.. We are all learning about Tegra 4 and 4i weather we a veterans or not. Ideas are best shared at the end of the day. But at least people on 4.2.2 can kill the OTA updater for now thus saving them from the updates that cause the bricks.

EDIT: (PC) I have a Mission if you Choose to accept!!!!

Operation SBK Finder:

In this mission we need the Following requirements .

Two Users Per Device Brand

Official OTA Devices to either Android 4.3 or 4.4.2 (If you haven't had a Official OTA and have super tools sorry you can not help!)

You must be bootloader Unlocked and rooted

You must have ADB Drivers and ABD access (If you have a rooted device then you have this)

You must be able to use ADB for searching for the SBK Key file and to parse logs for uploading (Logs being Logcat, Last_Kmsg and Dmsg!)

If you can do the above please PM me once we have a collection of information then we can probe the kernel into showing the key.

Commands you will be using via ADB with will be using SU (Hence Root Requirement). It will not brick your device as this is just a looking about and parsing logs.

List of Log Parsing Commands: (Thanks to TonyP's Thread!)

adb logcat -v time -d > logcat.txt

Next batch of commands is in adb shell with SU.

dmesg > /sdcard/dmesg.txt

cat /proc/last_kmsg > /sdcard/last_kmsg.txt

cat /proc/kmsg > /sdcard/kmsg.txt

Once you get these logs i would like you to zip them with just the brand name and if they are within the XDA's upload file size requirement attach them to your post if note please use an external site and link directly to the download please. Mega GDrive OneDrive would be ideal.

So why is the SBK key so important and why am i hunting it to find if its Brand or Per Device bound.

The main reason for this search is to find the SBK so you can have a Totally Unbrickable tablet as it currently stands and i have found this out myself is you can Only flash X amount of times using APX after the OTA updates before we get a SBK Fuse fail marker and or DK Fuse fail marker once this happens we get the famous Power Down loop i.e you can boot all the way to just loading android fully and then it goes to shutdown. This is due to the kernel looking at the status of the SBK and DK fuse, from what i can gather if it shows as fail the kernel simply tells the tablet to shutdown.

Now the SBK key when used in APX resets that check back to working and not false and also allows use to flash the device to our hearts content without the worry of bricking our device.

The current Unbricking is basically Software and that will cause a hard brick after time. the SBK key is for that hardware brick!!

So who is with me!!! lets find this key.

P.S: If like its counter parts a SBK key file might be in /sys/firmware/fuse and might be called secure_boot_key it might be called something else if you find it all i want is for now the know the location to it.