Hardware 360 Slim Hard Drive Not Registering

[Tsuteto]

So, here's the basic situation I'm working with for someone.

*They bought a 500GB hard drive (effectively, let's say from a flea market or something). When they plugged it in to their console, it worked fine.
*Transferred data from their old 250GB hard drive using the transfer data cable to the 500GB hard drive.
*500GB hard drive isn't recognizing in the console anymore. 250GB does.

What I'm still trying to determine:
*What the actual hard drive in the 500GB is.


Given the current situation, trying to figure out how to get the drive to register again. Thus, making the goals as such:
MAIN: Get the drive working and registering in the 360 without further issues (within capabilities)
SUB (but important still if possible): Retain the transferred data (saves, games, profiles, etc) on the 500GB drive

I've read basically that the situation is the security sector missing, thus the need of HDDhackr. Only thing is, not sure if the drive is a WD or not as of yet. But, if it's not, anything else that can be done?

No intent to do any sort of hacking to the system or drive or whatever, just trying to get it to work like standard within whatever plausible means as possible.

Thanks in advance.

 

[DinohScene]

Could be that the drive is failing.
Otherwise, crack it open and take a look.

 

[Tsuteto]

That's the current plan. I'm currently also ruling out a failing drive since this happened immediately after the data was transferred. But, going to do what I can, and if there's any other suggestions, that'd be awesome. Kind of unknown territory for me.

 

[DinohScene]

Harddrives can fail at any moment.
Could be a firmware error or as bad as bad sectors.