FORUMS: list search recent posts

new Macs and reverting to earlier operating systems

COW Forums : SAN - Storage Area Networks

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Bob Zelin
new Macs and reverting to earlier operating systems
on Dec 18, 2013 at 10:16:03 pm

boy, this is frustrating. The new Mac Mini's ship with OS X Mavericks. A popular piece of software that we use in our business does not yet support OS X Mavericks, and to my dismay, I can't seem to back - rev the new Mac Mini to an earlier operating system. I am trying to boot up off of assorted bootable external hard drives (which I use all the time for purposes just like this), and on the new Mac Mini, it just won't boot up. It sees it as a start up disk, but when you select it and try to boot up (or you boot up with the option key held, to select your boot drive) - it simply never boots up on an OS X Mountain Lion boot drive.

So it looks like any piece of software that you run better be supporting Mavericks if you are buying a new computer !

bob Zelin

Bob Zelin
Rescue 1, Inc.
maxavid@cfl.rr.com


Return to posts index

EricBowen
Re: new Macs and reverting to earlier operating systems
on Dec 18, 2013 at 11:44:23 pm

Its times like this that Microsoft's policy on legacy doesn't look quite so bad. This is the EFI road of the future.

Eric-ADK
Tech Manager
support@adkvideoediting.com


Return to posts index

John Heagy
Re: new Macs and reverting to earlier operating systems
on Dec 19, 2013 at 12:19:57 am

Have you tried creating a USB thumb drive boot image from the downloaded installer? You may be able to boot off that.

http://howto.cnet.com/8301-11310_39-57608836-285/how-to-create-a-bootable-o...

John


Return to posts index


Bob Zelin
Re: new Macs and reverting to earlier operating systems
on Dec 19, 2013 at 2:52:53 am

Hi John -
thanks for responding. I did not (I turned my 8gig USB thumb drive that had Mountain Lion on it, into a Mavericks boot drive) but USB is USB, and I have lots of variations of SATA drives that I stick into a OWC "toaster" with a USB connection, so I can boot off of various drives. I do this all the time (for plain OS, OS X Server, builds with FCP 7, etc, etc) for cloning. I do this all the time. And just last week, I had to back rev an OLDER Mac Mini from OS X Mavericks to OS X 10.8.3. So I know this process works. But this, today, was a BRAND NEW Mac Mini (theoretically the same thing) that came with OS X Mavericks installed. It worked wonderfully, but my application (I don't want to say - I spoke to the company, and they are frantically working on it for Mavericks) cant' run on Mavericks, and must run on Lion or Mountain Lion - so no big deal, just back rev to the older OS. BUT I CANT - not with this new Mac Mini.

Technically, I have no idea of how Apple can be "blocking" this from happening - the microprocessor just boots up and looks for the OS from the hard drive - but Apple did "something" that I just don't get, that prevents the Mac from booting up from the USB device (SATA drive in USB toaster). I tried multiple drives, and then tried ALL of those drives in the same toaster on my Mac Pro, and they booted up via the toaster just fine. So "something" is going on with the new computer builds. Apple really doesn't want anyone going back to older versions - why on earth would they care ? Like I said - you can go to "Startup Disk" - it sees the drive, and when you reboot- it never boots up on the USB device (that has the older OS on it).

Bob Zelin

Bob Zelin
Rescue 1, Inc.
maxavid@cfl.rr.com


Return to posts index

Steve Modica
Re: new Macs and reverting to earlier operating systems
on Dec 19, 2013 at 11:48:15 am

Usually, it's because the firmware on the machine has been updated. The new firmware probably has a dependency on Mavericks (for example, the format or location of the kernel it's pulling in). If you could downgrade the firmware, I'll bet you could get it to boot Mountain Lion.

Steve Modica
CTO, Small Tree Communications


Return to posts index

Eric Hansen
Re: new Macs and reverting to earlier operating systems
on Dec 19, 2013 at 5:24:34 pm

+1 to what Steve said. Apple updates the firmware.

I have purchased either refurbished Macs or older (but still new) Macs still in the sales channel for clients in the past for this reason.

e

Eric Hansen
Production Workflow Designer / Consultant / Colorist / DIT
http://www.erichansen.tv


Return to posts index


EricBowen
Re: new Macs and reverting to earlier operating systems
on Dec 19, 2013 at 6:58:13 pm

Or the firmware was updated and they prevent backward compatibility to streamline support and backend process. Keep in mind with EFI in the mix they can prevent booting to any boot manager they want. That is why EFI is going to change things.

Eric-ADK
Tech Manager
support@adkvideoediting.com


Return to posts index

Neil Sadwelkar
Re: new Macs and reverting to earlier operating systems
on Dec 22, 2013 at 1:26:25 pm

In general, Apple machines can boot off the OS that the machine shipped with and later, but seldom with an OS before that.
So, my one year old MB Air will boot Mavericks or Mountain Lion, but not Lion or Snow Leopard. Or a two year old MacBook Pro I have doesn't boot Tiger/Leopard but boots any OS after Snow Leopard.

-----------------------------------
Neil Sadwelkar
neilsadwelkar.blogspot.com
twitter: fcpguru
FCP Editor, Edit systems consultant
Mumbai India


Return to posts index

Chris Murphy
Re: new Macs and reverting to earlier operating systems
on Dec 27, 2013 at 10:17:28 pm

Well...at present the firmware is rather permissive. It'll run any EFI application or OSLoader thrown at it.

Where it gets possibly concerning is if/when Apple applies what they've done with iOS to OS X. I don't expect they'll have opt out equivalents to Microsoft's implementation of Secure Boot on x86_64. And as such it wouldn't surprise me if Apple effectively presents its customers with Restricted Boot instead.


Return to posts index


Chris Murphy
Re: new Macs and reverting to earlier operating systems
on Dec 27, 2013 at 9:12:14 pm

Apple has always done this since the beginning of time. What makes it more noticeable is when the cutoff is an x.0 release as is the case here. More often a new model comes out and gets a special build of 10.x.y and it will not boot less than the .y it came loaded with. I vaguely recall one or two times, maybe the Mac Pro faux-refresh, that we could go backward in OS version because, well, it really wasn't all that different hardware wise.

So what's going on is is that new hardware needs a new kernel and kexts to support things like the GPU, network, USB, and SATA controllers, and so on. Windows does this a bit differently in that an ancient base kernel can boot the system in a basic video mode, and then have recent video drivers added on. What would happen on say, linux, if you tried to use an old kernel and initramfs (equivalent to kext cache on OS X) on new hardware it was totally unprepared to run on, would be a kernel panic. Instead of doing something ugly, like kernel panicking that pretty Mac, Apple is probably inhibiting the very attempt at booting via the bootloader and firmware. The firmware likely knows what minimum boot.efi signature it will support. And if it doesn't find that, it doesn't offer it as an option.

So possibly you could grab the new boot.efi the machine wants, replacing the old boot.efi on the old system you need and see if the machine kernel panics (or worse, subsequently implodes an hour later for some reason - pretty unlikely it's usually a fast, deterministic failure if it's going to fail).

boot.efi is located in /System/Library/CoreServices.


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2019 CreativeCOW.net All Rights Reserved
[TOP]