I had always uses an old P1/P2/P3 laptop of days gone by...
...back from the days when laptops HAD serial ports...
But since getting the Visionsat with a USB update capability, I'm so spoiled I'll (try to) never go back to the serial mode again! -
Original factory firmware may require you navigate to the update screen and start the procedure manually.
Once you're into later firmware, ya just power down by the rocker switch on the rear, plug in the USB flash drive, power up at the rear (
and wait about 30 seconds), power up on the front, and wait... in
a minute or two, a firmware update screen should pop up and you can scroll through the versions it finds on your flash drive.
Pick one and go. - :up
edit: just don't put firmware on your hard drive, or every time you power up, it'll stop you and ask what version to load. -