Maybe it got missed so I will say it again. The Wii U USB ports provide appx 500 mA of power each. A usb hdd requires appx 1 Amp (which is 1000 mA), so you can see that there is not enough power coming out to run your drive. In comparison, a flash drive takes appx 100 - 150 mA (it is solid state, no moving parts like a hdd), so that is why a flash drive will work, since it is well under the 500mA max.
As far as CFG and 222, I will be honest and say I have no clue why CFG is prompting for that cIOS. When testing, everything worked fine on both drives I tested it on. I have the same exact setup as the guide, absolutely no differences at all. If i were to venture a guess (and it is just a guess) i would say that since the drive isnt being recognized cfg might be cycling through known cios trying to find one that will work. But none of them are going to work, since the drive doesnt have enough power to operate in the first place.
If you are hell bent on using that drive, try the Y cable. Or slice and dice like I did with a one amp usb charger. Chances are one of those will fix you up. 222 is not the problem though, so you might as well stop bringing it up.
Sent using the WiiHacks app. Please excuse the brevity, punctuation and spelling.