Honestly, I have not used it with unlimited mode. I was using the 5GB/month, so I paced myself (never more than 3 hours). I did notice it does run hot, though

Honestly, I have not used it with unlimited mode. I was using the 5GB/month, so I paced myself (never more than 3 hours). I did notice it does run hot, though. Maybe change the orientation of the MiFi. I haven't checked for firmware updates, either. Sorry I couldn't be more helpful.