This is kind of an update to a previous article focussed on puitting Debian onto a Dockstar. In the meantime — it’s two years since the Dockstar was famous (and cheap; or: famous because it was so damned cheap :-)) –, it’s SATA brother, the Seagate FreeAgent GoFlex Net (yes, a long name; STAK200 is the product code), dropped into the 30 EUR prince range, and, frankly, if you do use the USB bus for anything, like e. g. stream DVB off attached devices, you do not want your system’s normal disk I/O gets in the way here.
But, first things first, a warning: Seagate secretly ceased to support SSH login into the GoFlex Net (GFN). That’s at least true for my boxes ordered off Amazon in early August 2012 as well. I don’t know the story behind it, but Pogoplug devices historically were ssh-able into, so this change to me is an affront to the user base; for the time being, I’ll don’t buy anything from Seagate anymore (like: HDDs), except for more “hacker toys”.
The good news: Since the GFN features a 3.3V serial interface on a pin header, see this post for details, it’s still a nicely hackable device — especially for it’s current price –, so I’ll still go for it. Besides, the GFN comes with Pogoplug service, so that alone is a nice addon for an USB port, 2 SATA ports and a 1 GBit/sec network port at only a bit more than 30 EUR — even if you don’t want to hack it ;) 
So, as said, easy ssh-ing in, like I did on my first GFN about a year ago, is no more. But just remove the downside of the GFN, and you’ll see a pin header labelled J1, just connect your 3.3V serial converter to it (RX TX GND are the last three pins in the lower row) and, at 115k, you’re set ;)
Updating the U-Boot bootloader is a snap nowadays, thanks to Jeff Dozan and the people in his forum; just follow the instruction from Jeff after being connected to the booted GFN over serial. But beware: my GFN ceased to boot into default, i. e. Seagates Pogoplugged Linux, anymore. So, if you want to retain the default install (good idea e. g. on disk failures), you might need to dig around a bit more — I’m only interested in running plain Debian on the box, so I don’t mind much.
To use the GFN properly with Debian, you neet to fetch your GFN and SATA supporting Kernel from this thread, since Debian Wheezy still — as of 2012-08-19 — doesn’t support the Seagate GoFlex Net:
Error: unrecognized/unsupported machine ID (r1 = 0x00000c11). Available machine support: ID (hex) NAME 00000690 Marvell DB-88F6281-BP Development Board 00000691 Marvell RD-88F6192-NAS Development Board 00000692 Marvell RD-88F6281 Reference Board 0000078c Marvell 88F6281 GTW GE Board 00000a76 Marvell eSATA SheevaPlug Reference Board 00000831 Marvell SheevaPlug Reference Board 00000a63 Marvell GuruPlug Reference Board 00000bb6 Seagate FreeAgent DockStar 0000085b QNAP TS-119/TS-219 000009c6 QNAP TS-41x 00000b44 Marvell OpenRD Ultimate Board 00000939 Marvell OpenRD Client Board 00000915 Marvell OpenRD Base Board 0000089a LaCie Network Space Max v2 000008a0 LaCie Internet Space v2 00000899 LaCie Network Space v2 0000089b LaCie d2 Network v2 0000089e LaCie 5Big Network v2 0000089c LaCie 2Big Network v2 00000b1e HP t5325 Thin Client ffffffff Marvell Kirkwood (Flattened Device Tree) Please check your kernel config and/or bootloader.
To use the new kernel with SATA, be sure to have 3089 set in the U-Boot environment as the arcNumber if the GFN; Linux »recognizes« the ARM devices based on that, and if it’s set to the wrong number, you end up with a not booting Kernel or some features of your devices (like SATA on the GFN) aren’t supported.
That’s it, basically. Having to use a non-Debian kernel is a PITA for stuff like DVB, as you need to (re-) compile your kernel and all the modules yourself to make full use of it — but as I did this for my first GFN already; I don’t mind. The GFN is much better suited to act as a VDR server than the Dockstar, as SATA does not interfere as much as USB storage on the Dockstar with DVB reception/streaming.