Apple TV Hacks crew has recently provided a software patch that allows for external storage devices to be hooked up using the USB port to the Cupertino-crafted set top box.

Apple’s shiny gadget is already endowed with a 40GB internal hard drive, which can store up to 50 hours of video, 9,000 songs, 25,000 photos or a combination of each and is capable of delivering high-definition 720p output. The 40GB version costs $299.

Apple also announced on May 31 a roomier and more expensive version ($399), which packs a 160GB HDD under the hood, enough to store up to 200 hours of video, 36,000 songs, 25,000 photos or a combination of each.

The newly released patch is for version 1.0 of Apple TV software, so it won’t work on version 1.1 (although the Apple TV Hacks team is interested in knowing if someone finds a way to break that barrier).

According to them, in order to have the patch successfully applied, you need an SSH-enabled Apple TV, an Intel-Mac or an Intel-based *nix Mac (this is needed to run the script to patch the kernel on the Apple TV remotely), an installed version of Mac OSX 10.4 Tiger, an original, unmodified copy of the ‘mach_kernel.prelink’ file from the Apple TV and an external USB drive formatted using Journaled HFS+.

The team of hackers also insists for a backup of the Apple TV content, before running the script.

There is no official support in case something goes awry, but the forums at Apple TV hacks could prove useful for someone interested in finding out more about how to install or uninstall the patch.

Research firm iSuppli said that Apple is expected to sell 1 million Apple TV units in 2007 and 1.4 million in 2008.

The company also said that Apple is actually gaining very little from selling the gadget, driving the Cuppertino, CA-based company’s profits with Apple TV to unexpectedly low levels.

According to iSuppli, the total amount of money Apple invests in the 40GB hub’s components reaches $237, which means a gross margin of 20.7 percent for each unit sold.  By comparison, gross margin profits for iPods reach 40 to 50 percent.