So far, this is what has happened with my "upgrading"...
I had an old X360 Arcade, 20BG model. I cracked the HDD case, took out the stock 20 GB HD (SAMSUNG HM020GI), and did the "drop" trick (lol) into the new 360 SLIM 4GB model.
I plugged it in and fired it up. Boom. 20 GB hard drive, with everything i had before (DLC, profiles, etc), which i thought was lost forever. No firmware modding or anything, just essentially "plug and play"
Now, I have a 500GB USB HD [url=http://www.thesource.ca/estore/product.aspx?product=2513010&language=en-CA[/url]
Popped it out, its a nice Western Digital WD5000BEVT WD Scorpio Blue.
Now, i realize 360's Can only CURRENTLY support 320 GB. What i have done so far is backup my original 20 GB hard drive using Xplorer360 (both with the Backup Image feature, and by exporting Partition 3/Content option)
The 500 GB acer hdd came with a USB powered case for it, you just drop in the hd, snap it in, and plug into USB VIA 2 cables.
NOW, when i format the 500 GB hd, do i put the hddsbin file on it via the USB bootdisk, and then restore the image i created withXplorer360? Or do i just put put the hddsbin file on it, put it in the XBOX360 and format it, then copy only the PARTITION 3/CONTENT?