The issue comes from the change in signing key from Juniper in 2017

When you get this error follow these instructions.

More information is in this blog. http://puluka.com/home/networking/screenos/critical-screenos-security-flaw/

Once recovered by deleting the key upload the new key version from the download links posted on the Juniper web site.

Error: Bogus image – not authenticated!!!

This error will occur if you upgrade to the new ScreenOS image and still have the OLD signing key on your device.  The boot screen on the console port will show this message:

********Invalid image!!!
********Bogus image – not authenticated!!!

Fips check failed
Done

To recover from this error and allow the device to boot you need to delete the signing key.

delete crypto auth-key

Then reboot the device and the new ScreenOS should load.