Can't upload new firmware to C5x radios

New C5x come alive with a screen that asks to be upgraded to latest firmware version. Tried several different versions of the firmware (in different radios) all say “Invalid Image File” and then brick.

Now what?

Mimosa DID call. Solution was to go to the other address - It works but they are slow to boot, not smooth as far as working the same each time, but I did get them to unlock and accept the correct image file for PTP. My buddy said his took forever (like over lunch) to finally reboot. He put in (which is supposed to be PTP) but it did a lock up on his link in PTMP. Go figure.