I think we need to add some info into the wiki about using the 3TB drive with the GoFlex... since a hybrid MBR is required and a lot more work is needed.
Some problems I experienced were:
1) My 3tb drive came from the GoFlex series with the USB3.0 dock, and the GoFlex Home I bought seperately. I initially followed the walkthrough but it did not work- at all. So, I resorted to connecting the drive directly to a Ubuntu machine and installed gdisk there. When I used gdisk to create the partitions it would start my partitions at 256 instead of 2048. I think this was my biggest problem.
2) I was using nc on my machine and when I performed a printenv it would print a page and then disconnect. I thought this might be indicative of a corrupted uboot install, or possibly uboot wasn't completly configured to boot.
3) I was really concerned about the drive reporting as 748GB when I did allow it to boot with nc enabled, however after reading ajblowing's post, I realized it was expected. I don't think I saw a post like that from the OP, or maybe I overlooked it. Because of this, I followed davygravy's walkthrough here but couldn't get it to work over tftp, I loaded it via a usb flash drive with fatload outlined here, which then cleared all my uboot settings, and required a serial connection. Thankfully I had a usb->serial cable (from my dockstar days ). (I used this page to figure out the defaults values for the GoFlex).
4) Honestly, the main reason I was doing all of this was to run the system from the SATA drive instead of a flash drive, which should be more reliable. However, I also didn't expect the drive to continue to run hot as it was on the usb3 cradle. Can others with the system installed on the SATA drive advise if their drive is running warm to the touch? I guess I'll try to run it from a flash drive and see how it goes...
Anyways, thanks for the posts and I appreciate all the knowledge here.