Okay, good. There's good hope for a full recovery here.
There are two feature sets that could be hiding the real capacity of the drive:
* Host Protected Area feature set <--- most likely candidate
and/or
* Device Configuration Overlay feature set
The second one is particularly nasty, as what it does is cause the drive to LIE about supported features/capacities.. the existing hdparm cannot get around it, either. But I've been contemplating a new release that knows about such LIEs, and can bypass them when need be.
But here, it's probably just the "SET MAX ADDRESS" thing from the HPA feature set that's nigging things. This can be undone with a small program, running under a RECENT (2.4.21 recommended) Linux kernel.
I haven't written this program yet, but it's not terribly hard .. just takes an hour or two with the right kind of drive on hand to test it with. No, you don't need to send me your drive
. I just need to get back home where my IDE lab is at (out of town right now).
Nag me.