https://bitcointalk.org/index.php?topic=3731220.msg36938304#msg36938304

I think thats all the firmware that was released specifically for the Dragonmint.

Innosilicon firmware isn't guaranteed to work and I think
 they remove the old firmware

Actually I just checked and I have a copy of that firmware, I'll put it up here: https://drive.google.com/file/d/1zJJ3aMjl2hWmXOLDfxGvqO92aq8Uk7uc/view?usp=sharing