I am obviously a moron
The second 4.0 was available, I downloaded it an read the instructions.
I need a new radio and have download 1.57, but I can not flash it from the SD card (formatted FAT32, changed name ti ATHEIMG.nbh, entered bootloader and all I get is white screen that says "loading" forever) and I can't find instructions on how to upgrade a radio (have only ever upgraded complete ROM.)
I have spent the entire time since the thing was released looking for directions on how to upgrade the radio.
Feeling like a moron, but needing help.