Other World Computing has announced version 2.0 of its Unsupported UtilityX, which helps pre-G3 Macs use Mac OS X.
The freeware isn't backed by Apple, which doesn't support Mac OS X on pre-G3 Macs.
Other World Computing president Larry O'Connor said: "Until now, the only people that could use Mac OS X were those that bought a new Macintosh computer, or owned a G3 or G4 computer currently supported by Apple.
"Our goal with Unsupported Utility is to take care of the loyal Macintosh users who have older, unsupported systems. With Unsupported UtilityX, users can run OS X and revitalize their older, but still exceptional Macs. They will also be able to take advantage of new software products which are designed to only operate with OS X, as well as continue to upgrade their existing system with faster hardware products, rather than having to invest in entirely new systems."
The application brings Mac OS X to a range of legacy Macs, including the 7300, 7500 and 7600; the 8500 and 8600; 9500 and 9600, clones Umax S900 and J700, as well as Power Computing's PowerWave and PowerTowerPro.
Version 2.0 should also support recently released OS X 10.1.1 and future versions of OS X 10.1 as is, or with a few minor updates.