I finally found a way to do factory reset thanks to gran pc
How to reinstall FireOS
Botched your /system partition beyond recognition? Everything is broken? Dropped your #Kindle in a sea of piss and need to RMA it? Fear not! You can just reinstall FireOS and get it looking just as if we had never touched it!
First of all, you'll have to root your tablet. I'm assuming you know how to do this!
Once that's done, put this file -- https://s3.amazonaws.com/kindle-fire..._310084920.bin
-- in /sdcard/ (you can use adb push).
Then run these commands:
jesunoiMac:multidownload granpc$ adb shell
shell@android:/$ su -
root@android:/# cp /sdcard/update-kindle-126.96.36.199_user_310084920.bin /cache/update.zip
root@android:/# echo --update_package=/cache/update.zip > /cache/recovery/command
jesunoiMac:multidownload granpc$ adb reboot recovery
If everything went well, you should see the 'installing update' screen -- and once you're booted, we're back to stock! We did it!!!!!!
funny thing is I rerooted after the clean update and forgot all about OTA's being automatic of course. The damn thing upgraded to 188.8.131.52 which I searched has NO root exploit right now. I am wondering if I can do the same above steps to go back to 11.3.1 but that is a downgrade and I am worried about a brick although amazon new update is like an iphone you can't tell any difference haha
also is the above way how you install ICE or hellfire?