Just before "Maker Faire 2012" I bricked my Pi ( Red LED of death, aka no screen no network login, nothing ) Read up on Pi failures @ http://elinux.org/R-Pi_Troubleshooting
How I bricked it and how others also do ( This may happen to you! )
$ sudo apt-get update ; sudo apt-get dist-upgrade
$ sudo rpi-update 240
That worked but upon reboot, just the Red LED of DEATH.
Turns out it's not really hard to fix, what caused the issue in my case was that the first partition on the SD card was corrupt. It's a simple FAT ( not FAT32 but good old floppy style 16bit FAT ) had the wrong size.
Simple fix is to format it with FAT and no boot flag then copy back the files needed to start the Pi. Lucky I had a spare SD card that I got working and after upgrading it to latest I copied all the files from it's FAT partition to my main SD card.
The Pi now boots and is happy! All of my Drupal work is back up and running.
To avoid this mess reboot after upgrading ( required for any kernel updates ) then run “rpi-update” to get a new firmware.
Seems the SoC chip like a smart phone reads it's code from flash memory aka the FAT partition. This same recovery is how I un-brick phones. So goes to show that failures make some of the best learning experiences.