Custom Flashing to Nexus 7 - product info I am trying to flash the latest 6.0.1 build onto my Nexus 7 tab.
I picked MOB30X build from here

naveen@gandalf:~$ fastboot devices
015d2a4ffd181016    fastboot


But, when I do 

naveen@gandalf:~$ fastboot flashall -w
error: neither -p product specified nor ANDROID_PRODUCT_OUT set


What is this product about? 

Further,
Looking like the build comes with a nice installation file flash-all.sh
While running

fastboot -w update image-razor-mob30x.zip


I'm again hitting this error


  checking product... 
  FAILED


Here's the complete log file
You need to set ANDROID_PRODUCT_OUT in /etc/environment.
You may have a folder with boot.img and system.img etc. in, this is the right folder.  

Example: 

ANDROID_PRODUCT_OUT=/path/to/folder/with/images/


After that you can call sudo fastboot flashall -w   

It also works for self builds.