2006/2007 Mac Pro (1,1) from Yosemite TO Lion

Discussion in 'Mac Pro' started by pettedemon, Feb 17, 2015.

  1. pettedemon macrumors newbie

    Feb 17, 2015
    I installed 10.10.2 in my mac pro 1.1.
    Yosemite doesn't work very well. There are too problems.
    It is possible overwrite the EFI and return on LION ?
  2. Morpheo macrumors 65816


    Feb 26, 2014
    Not sure what you mean by "overwrite the EFI". The only way to go back to a previous OS version is either via a Time Machine backup or a clean install. If your system is working with Yosemite, I would suggest backing up your files first, and go for a clean install.
  3. pettedemon thread starter macrumors newbie

    Feb 17, 2015
    I installed a clean yosemite, I upgrade to 10.10.2 but there are too problems.
    So I try install Lion on new hard disk and it doesn't work.
    I was afraid there had been an update to the System BIOS level and you could Turn back.

    I try an extreme way.. I try to install Snow Leopard and it works.
    Maybe my Lion was corrupt?
  4. westrock2000 macrumors 6502a

    Oct 18, 2013
    I put Mavericks on mine and I think it's a good compromise. Lion had several issues related to network sharing that were really impeding my systems role as a server. Particularly SMB sharing. And the screen sharing bug.

    But Mavericks has been great. I use a very cheap ATI HD5450 video card ($30)

    You can see my instructions here

    Just get Mavericks running on the Geforce card. Then install ATI card in another slot. Follow those directions and make sure OSX recognizes it. Then shut down and remove the Geforce and put the ATI in the bottom slot.

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3 February 17, 2015