totally rewritten description of BBB update process

if people are interested:

did i forget anything important?


Two things.

  1. On the how to update section, it might be nice to give a couple of example on how to actually transfer the image file to a raw SD card, or at the very least, link to a few examples.

  2. I’ve seen Gerard mention a couple of times that upgrade process comes very close to drawing the maximum amount of current that USB 2.0 provides (500mA). It should probably be worth mentioning that running the BBB from a 1A or better supply is highly recommended when flashing.