New Xserves ship with 10.6 Server but need downgrade to 10.5

[CharlieM]

Has anyone dealt with new Xserves that ship with 10.6 Server, but need to be downgraded to 10.5? Since the hardware has not changed, I'm assuming that 10.5 Server will install, however I'm wondering whether the serial number for 10.6 will work on a 10.5 install.

[bs3375]

This is always a bad idea. Apple may have not changed the hardware on the surface but I would almost guarantee they changed something in the firmware.

Unless the server (or any Mac for that matter) shipped with a drop in kit allowing you to install either 10.5 or 10.6, you should never install a version of the OS that is older than the machine. Even if you can get it to work, either by cloning or luck, you'll most inevitably start running into issues.

Case in point, we have a client who bought 2 Mac Pros. One had the drop in, the other didn't. Virtually identical in every way. The client requested that Leopard be put on both machines for maximum compatibility with their current software and now, two weeks later, the machine that shipped with Snow Leopard has audio issues that disappear when booted into 10.6.

That being said, unless Apple changed something recently, 10.6 serial numbers can be used to legitimately license 10.5. Apple provides this as a feature so that resellers can sell to an enduser that was slow to upgrade from 10.4 to 10.5 and can't, for whatever reason (usually hardware) jump to 10.6.

[abstractrude]

bs3375 is right but you can definitely run 10.5 on xserves apple is shipping.
also, there are two builds of OS X. there are machine specific builds and standard builds. dont know if this applies to os x server.

Here is what my 10.5 new xserves are running on.

Boot ROM Version: XS31.0081.B04
SMC Version (system): 1.43f4

[CharlieM]

Thanks bs3375. Agreed that downgrading a machines factory-installed OS is not ideal. But I'd think it would be less problematic than introducing a Snow Leopard machine into an existing 10.5 Xsan environment.

[morphenine]