Yep, partially... This is as good as it is going to get without the kernel being hacked. Download should be available from Xbox Scene soon.

Info from readme file:

Hddhacker v0.5B by the Specialist.

This tool has only been tested by me. It worked for me. While great care
has been taken, this tool may contain bugs and therefore may seriously
harm your HDD. Use at own risk !!!

What:

This tool will allow you to use HDD's that are not 'certified' by Microsoft.
This specific tool is written for use with the Western Digital BEVS series
only !

How it works:

x360 HDD's contain information on sector 16 about the HDD: the HDD serial
number, the model, the firmware version and the size in sectors is stored
here. The x360 asks the HDD to identify itself, by sending an 'IDENTIFY DEVICE'
ATA to the HDD. It will compare the returned information to the info that is
stored on sector 16. This information on sector 16 is signed and thus can not
be changed. This tool will mod the FW from the WD HDD to comply with the
information on sector 16, so that the 'identify' information will match the
information on sector 16 and your x360 will accept the HDD as valid.

How to use:

Get yourself a Western Digital SATA BEVS HDD. Copy sectors 16 - 22 (7
sectors) from a valid x360 HDD to the Western Digital. Then, boot to dos
(not a dos box from windows) and run this application. Make sure that you
have ONLY this Western Digital drive connected to your sata controller, have
the other devices disconnected. Then follow the instructions on screen. Keep
in mind that you have to start the utility from a writable path if you want
to create an 'undo' file (it will save it to the path you've started the
tool from). Make sure that you have FIRST copied the sectors 16-22 onto
the drive, BEFORE using this tool ! The tool will need that info on sector 16,
otherwise it doesn't know how to mod your FW.

After the tool has flashed your drive, turn off your computer, wait a few seconds,
restart your computer and re-run the tool. The tool will tell you then whether the
whole thing was succesful.

FAQ:

Q. Will this tool allow me to connect a 500 gb drive to my x360 ?
A. No. The information on sector 16 is signed and can't be changed. You can
only use size where you have a valid signature for. In otherwords, if a
bigger HDD comes out, you can use that signature.

Q. With which HDD's does this work with ?
A. It should work with *ALL* Western Digital HDD's from the Scorpio BEVS series.

Q. Do I need the same size WD HDD as the size on sector 16 states ?
A. No. You can use bigger HDD's, but you can't use more than the size stated
in sector 16. You can NOT use smaller HDD's than the size   on sector 16
states. For example, you can use a 40 GB HDD with a sector 16 from a 20 GB HDD, but
not the other way around of course.

Q. Can I use the HDD in my PC again ?
A. Of course. The tool comes with an 'undo' option, that will restore the
original size. For example, you use a 40 gb WD HDD, you copied 16 sector
from a valid xbox 20 gb HDD, so the tool will transform your 40 GB HDD into
a 20 gb HDD. However, you can restore it to 40 gb anytime you want. The tool
has the ability to create an 'undo' file, BUT this current version
doesn't contain the option to flash it back. The next version will be able
to do that. Just create the undo file and wait for a new version, should be out
in the near future.

Q. Why do I need more sectors than sector 16, if that one stores all the info ?
A. The following sectors contain the MS copyright logo and is checked for by
the x360. Without it, the x360 will reject the HDD.

Q. I have a x360 core version and want to use this hack to buy a cheap HDD.
But how do i connect it ?
A. MS uses a specific connector. While it doesn't look too complicated to
create your own, I haven't tried this myself, but I'm sure there are some creative
hardware minded souls out there that should be able to think of something

Q. How do I copy the 7 sectors ?
A. You can do so with tools like hex workshop, winhex etc. If you don't understand these
tools, ask somebody who does.

Q. The tool doesn't detect my HDD !
A. First, make sure you are running it from dos, not from a dos box under windows. Then,
try playing with the SATA/RAID settings in your bios. Not all SATA controllers are
supported. I use a VIA controller, which works perfectly. However my tool fails to
see my Promise controller. I'll see if I can support more different controllers in the next version.

Q. Your tool says everything was succesful but the drive doesn't work in my 360 !
A. Make sure you have copied sectors 16-22 correctly and didn't change any data.

Q. Could you do this for my Seagate, Maxtor, Samsung or whatever drive too ?
A. Yes, but I don't have plans to do so. The cheapest WD drive (40 gb) ships
for about $50 and thus is one of the cheapest. It is a lot of work to
convert this tool for usage with other brands and I don't think it is worth
the trouble.

Q. So how do I get my 80 GB WD HDD working as 80 GB in my x360 ?
A. There are 2 options: wait for a release by MS, so you can use that sector
16 (or hope that the rumours that they ARE out there already are true) OR
wait for the kernel to be hacked. These are the only 2 options.

Q. Where can I donate ?
A. Nowhere. Just enjoy

Thanks to: Team MODFREAKz for his initial logic board experiments, Loser for his
findings on the sector 16 and everybody else at XBH.

TS in jan 2007