Paths to running Snow Leopard on new, Lion Macs
While not recommended by Apple, it has been done by a bunch of folks, mostly using three variations on the same theme:
* Using an "old" Mac that can successfully boot from SL install discs (usually the 10.6.3 retail discs) and TDM (direct process);
* Using an "old" Mac to create an image on an external HDD that is them physically moved into the "new" Mac;
* Using an "old" Mac to great a bootable image on an external HDD, then using a low-level copy program like SuperDuper! to copy that image to the "new" Mac's HDD.
See comments on other forums for details.
https://discussions.apple.com/thread/3209335?start=12&tstart=0
https://discussions.apple.com/thread/3264421?start=320&tstart=0
Target Disk Mode method - Downgrade Your Mac
I used the TDM method and it worked fine. The "target" machine is a new (not refurb) 15" MBP (8,2) shipped new from Apple in March, 2012; the "old" Mac is a 15" MBP (5,1). No problems to report so far; Eudora still works well, so Rosetta is still in place and running. Performance is exceptional; all the cores are definitely being exercised when called upon (games, mostly).
As far as 5,1 Mac Pros: the main problem here is that 5,1s originally shipped with 10.6.4, which is not available in the wild; the systems will not boot from the retail (10.6.3) SL disks. I have two MP 5,1s, both originally shipped with 10.6.x, that are running 10.6.8. When I had trouble with one of their boot HDDs, I had to use my older (5,1) MBP to create a bootable HDD for it. Works fine. I would expect *any* MP 5,1 to work with SL, as that HW is now quite old, but one might have to jump through some hoops to get there, and Lion volumes will not be properly accessible when booted as SL (if one wants dual-boot to be available). If Ivy Bridge-based MacPros come out, I'd say all bets are off; they may run MtnLion (or later) only.
YMMV; proceed with caution, sharp curves with steep drop-offs may be ahead.
As far as the original question (can new 5,1 Mac Pro's be "downgraded" to run Snow Leopard)...here are a few Apple links that may shed a bit more light on things (no guarantees):
Mac OS X versions (builds) for computers
Finding your Mac OS X version and build information
Don't install a version of Mac OS X earlier than what came with your Mac
The 3rd link may be the most enlightening...since it basically says "You should not install a version of Mac OS X earlier than that which came with your Mac."
We usually don't run into this sort of problem...because Apple usually updates each model line (MacBook Pro, iMac, Mac-Mini, MacBook Air, Mac Pro) at least once/year...sometimes twice in the same year. But since it has been so long since Apple has updated the Mac Pro lineup...we are running into this "funky" OS issue/problem!
- Nick
While not recommended by Apple, it has been done by a bunch of folks, mostly using three variations on the same theme:
* Using an "old" Mac that can successfully boot from SL install discs (usually the 10.6.3 retail discs) and TDM (direct process);
* Using an "old" Mac to create an image on an external HDD that is them physically moved into the "new" Mac;
* Using an "old" Mac to great a bootable image on an external HDD, then using a low-level copy program like SuperDuper! to copy that image to the "new" Mac's HDD.
See comments on other forums for details.
https://discussions.apple.com/thread/3209335?start=12&tstart=0
https://discussions.apple.com/thread/3264421?start=320&tstart=0
Target Disk Mode method - Downgrade Your Mac
I used the TDM method and it worked fine. The "target" machine is a new (not refurb) 15" MBP (8,2) shipped new from Apple in March, 2012; the "old" Mac is a 15" MBP (5,1). No problems to report so far; Eudora still works well, so Rosetta is still in place and running. Performance is exceptional; all the cores are definitely being exercised when called upon (games, mostly).
As far as 5,1 Mac Pros: the main problem here is that 5,1s originally shipped with 10.6.4, which is not available in the wild; the systems will not boot from the retail (10.6.3) SL disks. I have two MP 5,1s, both originally shipped with 10.6.x, that are running 10.6.8. When I had trouble with one of their boot HDDs, I had to use my older (5,1) MBP to create a bootable HDD for it. Works fine. I would expect *any* MP 5,1 to work with SL, as that HW is now quite old, but one might have to jump through some hoops to get there, and Lion volumes will not be properly accessible when booted as SL (if one wants dual-boot to be available). If Ivy Bridge-based MacPros come out, I'd say all bets are off; they may run MtnLion (or later) only.
YMMV; proceed with caution, sharp curves with steep drop-offs may be ahead.
