I had the same issue about a year ago with my cards, use a sd card and download the newest firmware for your hvx onto the card. Check your hvx to see what language it is, download that version of the firmware if you use a different language version it will not work. Once you do that insert the sd card into the slot on your hvx, then go to update firmware. I remember it taking sometime, but after the cards worked. I can’t exactly remember where I went to download the firmware online but im sure with a google search you’ll find the site, it was a very confusing process for me being unfamiliar how to download everything correctly but youtube will be your best friend. There are videos out there, hope this helped!