A second "mod chip," an add-on chip for the console that lets consumers play pirated discs and other applications on their consoles, is now available. And for more ambitious hackers, instructions have begun to proliferate on the Web for building homemade Xbox modifications. The first Xbox mod chip, the Xtender, went on sale late last month through specialty retailers such as Hong Kong-based Lik Sang. Late last week, those retailers also began offering the Enigmah-X and the XboxChip, a differently packaged mod chip based on the Enigmah.

Like mod chips that have proliferated for other game consoles, including Sony's market-leading PlayStation 2, the Xbox chips disable security features built into the console. With a mod chip soldered into the box, owners can play bootleg copies of games burned onto CD or DVD discs, or games designed for other geographic regions that normally would be blocked by the console's regional encoding system. The Xbox mod chips also allow hackers to run PC-flavored software on the console, including a media player already in circulation. There is also a growing effort to port the Linux operating system to the Xbox. While the mod chips permit the use of bootleg copies of Xbox games, analysts have said they pose little threat to Microsoft because few Xbox owners would even consider the technologically daunting task of installing the chips.