As you may have known, all non-slim Ps3 systems had an option to run other operating systems such as Linux, but the following PS3 firmware update (3.21) is going to disable that ability, forcing all consoles to be equal.
An official statement has been written on the PlayStation Blog by Patrick Seybold:
“The next system software update for the PlayStation 3 (PS3) system will be released on April 1, 2010 (JST), and will disable the ‘Install Other OS’ feature that was available on the PS3 systems prior to the current slimmer models, launched in September 2009. This feature enabled users to install an operating system, but due to security concerns, Sony Computer Entertainment will remove the functionality through the 3.21 system software update.”
