drivekey is just a softmod on a chip and adding one to a dead drive will do nothing. They are worse than a regular chip as well and only really of use for drives that do not support chips or those who are seriously afraid of soldering or getting on of those clip on devics.
flatmii is a drive replacement chip and will function in place of a drive using your PC to do the hard work, while it may not matter here it will not however allow wii drives to play copied games (you will still need a chip/softmod for the drive).
All this being said many will point you in the direction of the USB loader these days.