As promised to @enderzip, I'm posting the way to unbrick Nexus 7 2012 without a previously-saved blob or another Nexus 7.(Sorry for the long delay, but I just got time and access recently)
1.Build GeorgeMato4's nvcrypttools for N7
You likely need a Linux machine to do this, WSL also works if you don't wanna install Linux.
Here I'll use Debian 10 under WSL2.
Then use the following commands to download and build nvcrypttools for N7:
Here you'll get mknvfblob binary.
2.Generate your device's blob using bootloader and BCT
And BCT for your device:
Copy them to the nvcrypttools directory.
Then generate blob using the following command: (cd to your nvcrypttools directory first)
Replace yourSBK with actual SBK of the bricked Nexus 7.
Then change permissions (the mknvfblob always outputs with a strange --wx------ perm )
Here you've got your device's blob as test.blob, which can be used in wheelie and nvflash.
the AndroidRoot team