going back to SL from Lion

[halledise]

if one were to purchase an about-to-be-released Mac - MBAir, Mini, MacBook, etc - which comes with Lion pre-installed and (presumably) a Lion install usb stick/dvd - will one be able to 'go back' to Snow Leopard if one's not happy with Lion or will there be some physical restriction as in a firmware update or similar?

I realise this is something of a hypothetical query, but that is what Mac Rumors peoples is good at

 

[Kyllle]

I'm sure you could, you'd just have to get a snow leopard disk somewhere, you might have to buy it from somewhere like ebay, as I'm pretty sure apple won't sell it after lion comes out.

 

[Scottsdale]

No, if it pre ships with Lion, you will never be able to go back to Snow Leopard with it. The SL install disk will not have drivers for the new version of the MBA unless it ships with SL. You can go forward with Macs but not back to a version before the release it ships with.

If you buy an Nvidia-based MBA, discounted after the update, sure you could use either OS if you want.

 

[WardC]

You must realize that the Lion install on the new (unreleased-yet) MacBook Airs will include special drivers for Thunderbolt, etc which cannot be found on any Snow Leopard install. Apple may restrict OS compatibility to 10.7+ on the new MacBook Airs. This has been the theme of Apple recently with new machines, only supporting the shipped OS as the lowest # of OS seed supported. For instance, 2010 MacBook Airs cannot support anything less than the special version of 10.6.4 that shipped with them, and the 2010 Mac Pro towers will not work properly unless you use the special 10.6.4 install or later that came with them, due to the Graphics card drivers in that release. Any other installs may not work, or may render your machine unusable.

Interesting enough though, in the old days it was sometimes possible, as System 6.0.7 would run just fine on some of the machines that shipped with System 7. But ever since 7.5 came around, you must use the OS it shipped with, or later (i.e. 7.0, 7.1, 7.5, 7.5.1 will not work on a machine that shipped with 7.5.2) Only that OS or later was supported. In OS X, Apple has not had backwards compatibility with any machines.

 

[softasfur]

Going back to SL possible

You have to install the video kexts, 2 of them, from Lion into SL. Otherwise you can install snow leopard on the Macbook Air but you will only see video with an external monitor. I found them on kexts com.

 

[AppliedMicro]

You have to install the video kexts, 2 of them, from Lion into SL.

Do you happen to know which ones?

 

[softasfur]

@AppliedMicro I did get it to work but it still was buggy and slow. I ended up returning it. Looks like it's a heavy MBP or a previous Air without Thunderbolt.

 

[AppliedMicro]

Thanks for your feedback.
Seems to look the same as on the Mac mini then...