How to reverse clipped/resized HDD drives?

[BmanRulesYou21]

Hello

Recently I bought 4 WD Red 6TB NAS drives from this seller on Ebay, knowing that they were clipped to 1.2TB and with the expectation that I could reverse that process. I did some research before into using HDD Capacity Restore Tool (which I wasn't able to get working because it only runs on a 32-bit installation of older windows versions.), SeaTools, and finally HDAT2. After using these tools and not being able to restore to full capacity I've become lost for what I can possibly do moving forward other than flashing different firmware to the HDDs. I have no idea where to source the tools/firmware itself to even go about this and was wondering if anyone else had any info on this process. 

NO, it isn't partitioned weird, the drive shows a max capacity of 1.2 terabytes with 2344306405 LBA Sectors. 

NO, there are no sectors hidden behind HPA/DC0, HDAT2 has said that it should have access to the "Maximum amount of sectors" that it has.

 

I paid 35$ a pop for each of them so I don't feel scammed out of what I bought, that's a pretty reasonable price for a 1tb drive. Just wonder what could have been for my NAS that I used an old prebuilt for that only has 4 Sata ports and no pcie slots..