...when my RPi would not boot right after I finished some power supply work on the 'Bot!?!? I was so convinced that I had fried it that I was researching diagnostics to prove the point. All I got on power on was a red light. No green flashes. Nary a one.
What I guess I did not realize is that a bad SD card will result in the same lack of green flashing. That is good news. Also on the good news front is that I have a backup of the boot partition and when I dd'ed it back onto the SD card everything in 'Botland was right again. Err, well not quite.
Somehow, whatever took out the boot partition, also caused some pretty significant damage to the primary partition where everything else lives. But not to worry we have a backup of that as well, right? Err, well not quite. You see, I give the advice, but I don't have to follow it! The backup that I have is not exactly up to date. I am not sure how up to date it is, or is not, so I am going to have to rebuild it.
-----UPDATE as of 5/12/2012 ----
It is the next day now and I am still recovering from the above fiasco...the part where my backup of the primary partition was not where I remembered putting it! So I am re-creating the entire configuration, rationalizing that it is something I wanted to do anyway, and swearing that I will make good backups from now on!