[TriLUG] Error checking for dd?

[Nathan Yinger via TriLUG]

Does anyone know a good/easy way to check for errors when writing an image
to an SD card with dd? I keep having to flash RPi SD cards multiple times
before they work properly.

After writing an SD card, I tried using dd to copy it back into a file to
diff with the original, but it cloned the entire SD card, including blank
space. (The original image was 45MB, and I stopped the copy back at 100MB).

~Nathan Yinger