Secret Firmware Update Lets Late '08 MacBooks/Pros Use 8GB of RAM

Discussion in 'MacBook Pro' started by iPhone1, Mar 5, 2011.

  1. iPhone1 macrumors 65816


    Apr 2, 2010
    San Diego, CA
    via iClarified

    OWC has discovered that a 'secret' firmware update has enabled access to 8GB of RAM on late '08 MacBooks.

    In late 2009, an EFI Firmware Update was released to address the buzzing noises coming from the optical drive. However, it seems that somewhere along the line, Apple changed this update without notating it anywhere.

    Whether any other elements were affected by this change is undetermined, but it did change memory addressing; with the later version of the update installed, you could address a full 8GB in Snow Leopard. Unfortunately, Software Update doesn’t show this version as being different from the previous one, so users wouldn’t be notified if they had already updated their firmware to the older version.

    This discovery applies to the following MacBook models:
    ● MacBook 13.3" 2.0GHz and 2.4GHz
    ● MacBook Pro 15" 2.4GHz (All)
    ● MacBook Pro 15" 2.53GHz model w/ExpressCard Slot (Late 2008)
    ● MacBook Pro 15" 2.8GHz model w/ExpressCard Slot (Late 2008)

    Check your BootROM version in System Profiler and make sure its MBP51.007E.B05 for MacBook Pros and MB51.007D.B03 for MacBooks.

    Then download and install the "secretly" updated firmware from here:
    ● MacBook Pros (MacBookPro5,1): MacBook Pro EFI Firmware Update 1.8
    ● MacBooks (MacBook5,1): MacBook EFI Firmware Update 1.4

    Finally, make sure you are on Snow Leopard 10.6.6 then upgrade your RAM to 8GB. I'll be doing this first thing tomorrow morning!
  2. cube macrumors Pentium

    May 10, 2004
    I don't understand. March 2009 MBP has MBP51.007E.B05 but is supposed to support 8GiB RAM out of the box. Where's the difference?
  3. wesrk macrumors 6502a

    Nov 4, 2007
    seems like this is meant for the late 2008 models.
    I still have an early 08 model sadly, so still 4gb of ram for me only… although I tried 6 gb and worked fine a while ago, I'm not going for 8gb.
  4. Hexley macrumors 6502a

    Jun 10, 2009
    I have the late 2008 15" 2.4GHz MBP. My question is can it accept RAM faster than 1067MHz DDR3 like say 1333Mhz DDR3?

    I wish my early 2008 15" 2.4GHz MBP can also accept more than 6GB of ram as well.

    I remember that 133MHz SDRAM can be accepted in place of 100MHz SDRAM a decade or so ago.
  5. iMacDragon macrumors 68000


    Oct 18, 2008
    Generally speaking you can always stick faster ram than spec in, it will just work at the slower speed.
  6. santos79 macrumors regular

    Feb 25, 2009
    OWC's explanation doesn't make much sense

    I am an owner of a first-generation unibody MPB (2.4Ghz CPU) that I bought in March of 2009 and of course I was delighted at the news and have already purchased the 8GB upgrade.

    But has it dawned on anybody else that OWC's explanation doesn't make much sense at all? OWC's site claims there was a "secret" upgrade, but doesn't provide the number of the old 1.8 EFI Boot ROM revision number. OWC even says it doesn't know anymore, and I have yet to read in one of the forums that somebody actually had the old revision number.

    I updated myself as soon as 1.8 was available and have since had the Boot ROM number MBP51.007E.B05. That's the number that supposedly was the result of the "secret" update.
  7. Hexley, Mar 8, 2011
    Last edited: Mar 8, 2011

    Hexley macrumors 6502a

    Jun 10, 2009
    If sticking 8GB into a late 2008 MBP is now allowed & improves performance, who cares if it doesnt make any sense.

    OWC did mention that it works with the EFI firmware under OS X SL 10.6.6. For all we know Apple's artificially restricting limits to RAM based on what they themselves put into their machines. If Apple starts shipping 16GB into their future notebooks we may be allowed to up our notebooks to 16GB as well.

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