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“Secret” Firmware lets Late ’08 MacBooks use 8GB.

Thursday, March 3rd, 2011 | Author: and

Every once in a while, a blip on the radar comes up, letting us know that there’s something not quite right in our little corner of the Mac Universe. This time around, it came in the form of Tweets directed to us, as well as in posting in popular Mac forums.

As it turns out, several other memory vendors—along with some Late 08 MacBook/MacBook Pro users—have laid claim to these machines working with 8GB of RAM. This was contradictory to our testing in December 2009 which quite clearly showed that while these models recognized a full 8GB, if an application addressed more than 6GB, the system would slow down significantly.

Not being the type to just let these sorts of claims to go unchallenged, we went back to our testing lab, grabbed the affected model machines, running 10.6.6. and dropped an 8GB upgrade kit in them.

The results were exactly the same as in 2009, lending credence to our conclusions, but the sheer number of claims to the contrary led us to continue searching—and the trail ended at Apple.

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.

The practical upshot of all this is that if you installed the EFI Update when it first came out, like we did, you would have gotten the old code, which meant your computer would only address 6GB properly. Those who didn’t upgrade until after Apple changed the updater got the newer firmware, which allowed proper addressing of 8GB.

Once we manually installed the “updated” version of the EFI Firmware in our test machines, they were able to address 8GB normally, without any crashing or slowdowns.

How do you ensure your Late ‘08 MacBook/MacBook Pro can address 8GB of RAM?

First, you want to make sure you have one of the affected models:

  • MacBook 13.3″ 2.0GHz and 2.4GHz
  • MacBook Pro 15″ 2.4GHz model w/ExpressCard Slot
  • MacBook Pro 15″ 2.53GHz model w/ExpressCard Slot
  • MacBook Pro 15″ 2.66GHz model w/ExpressCard Slot
  • MacBook Pro 15″ 2.8GHz model w/ExpressCard Slot
  • MacBook Pro 15″ 2.93GHz model w/ExpressCard Slot

Next, check the Boot ROM Version in your System Profiler.

  • MacBook Pros with a Model ID of MacBookPro5,1 should have a Boot ROM Version of MBP51.007E.B05. 
  • MacBooks with a Model ID of MacBook5,1 should have  a Boot ROM version of MB51.007D.B03
  • Machines with other Model IDs are not affected and don’t need an update.
  • **IMPORTANT NOTE: EFI Firmware Update 2.8 was released on February 28, 2012 for the Later 2008 MacBook Pro. If you have installed that update, your Boot ROM version will be MBP51.007E.B06. If you have this update installed, you’re already able to install the 8GB without any problems and don’t need to perform further updates to install more RAM.

If your Boot ROM version does not match the numbers above, download the appropriate firmware updater for your model machine and install according to the instructions:

Once you have ensured that the Boot ROM is the correct version, make sure your Operating System is updated to OSX 10.6.6. You must be running Snow Leopard or later to address 8GB on these systems, and our testing was done with 10.6.6, which is the earliest version we’re currently supporting for this.

Pardon us for our initial skepticism on this larger memory capacity finding. We had some pretty good reasons for it. First, this is the first time in our recollection that an EFI update and a dot version OS update both combined to affect memory addressing. Secondly, this reminded us of when after we were the first to qualify 2007-2009 Core 2 Duo MacBook Pro and MacBook models supporting 6GB max without experiencing a dramatic system slowdown, certain memory resellers pushed the same idea about 8GB compatibility.

Or in other shorter words, if we can’t prove either benchmark performance gains and/or system stability, we’re just not going to market a memory upgrade just to pad our MaxRAM credentials.

Your trust in us is more important than any other objective here.


Judging by the sheer number of comments, there seems to be some confusion as to which MacBooks and MacBook Pros this update applies to. We’ve created a simple flowchart that should help clear up some of the confusion.


EFI Firmware Update 2.8 was released on February 28, 2012 for the MacBook Pro, to resolve graphics issues. It does not disable the 8GB compatibility the previous firmware revision granted.

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    1. Arun says:

      Thanks for such a great/informative article. After updating my MacBook5,1 (4GB RAM) to Mavericks, I have been experiencing sluggish performances quite now and then. So, I was wondering if I can upgrade the RAM to 8GB, which I will certainly do now after reading this article.

    2. MADPRODUCER says:

      hi! i would like to know if the 2008 late mac will take full advantage of the 8gb of ram.. isn’t the main board limited to 4gb or something? im a noob ok, my question is, will it be good deal for the money or i will be ok with 6gb ram;


    3. Greg says:

      Model Identifier: MacBook5,1
      Boot ROM Version: MB51.007D.B03
      SMC Version (system): 1.40f2
      Software OS X 10.9 (13A603)

      I tried installing 8GB of Corsair CMSO8GX3M2A1333C9. It didn’t work. I ordered a replacement thinking it was faulty memory. Still didn’t work. Two different sets of errors though. The first couple resulted in long beeps. The second pair just kept spinning the optical drive without any beeps.

      I tried also resetting the SMC and PRAM. No luck.

      Any advice?

    4. Kanchan says:


      My specs have Boot ROM Version: MBP51.007E.B06 (not B.03) and I am running Maverick, is this going to make a difference in relation to the certification for 8GB RAM?


      • OWC Ben says:

        Your computer has the latest firmware from Apple which came out on Feb 28, 2012. Your computer will be still able to handle 8GB of memory without issue.

    5. Dean says:

      Hi i was wondering if I can run 8GB on my late 2008 MBP. Using Mavericks now. Thank you for help and advice.

      Model Name: MacBook Pro
      Model Identifier: MacBookPro5,1
      Processor Name: Intel Core 2 Duo
      Processor Speed: 2.4 GHz
      Number of Processors: 1
      Total Number of Cores: 2
      L2 Cache: 3 MB
      Memory: 2 GB
      Bus Speed: 1.07 GHz
      Boot ROM Version: MBP51.007E.B06
      SMC Version (system): 1.33f8
      Sudden Motion Sensor:
      State: Enabled

    6. Jose says:

      Model Name: MacBook
      Model Identifier: MacBook5,1
      Processor Name: Intel Core 2 Duo
      Processor Speed: 2 GHz
      Number of Processors: 1
      Total Number of Cores: 2
      L2 Cache: 3 MB
      Memory: 2 GB
      Bus Speed: 1.07 GHz
      Boot ROM Version: MB51.007D.B03
      SMC Version (system): 1.32f8

      Operative System Version: 10.9.1

      The upgrade to 8bg RAM doesn’t work.

      Any ideas?

      Thank you.

      • OWC Ben says:

        You have the proper firmware to run 8GB (2x4GB) of memory. I recommend trying to clean the memory module. Take a clean pencil eraser and gently rub it along the metal contacts on the memory and follow that by using a microfiber towel along with rubbing alcohol to clean the metal contacts on the memory, this should insure that the memory is getting a solid contact with the computer

        If that doesn’t resolve the issue, I would try both and SMC and PRAM reset.

        SMC reset: http://support.apple.com/kb/HT1411


        PRAM Reset:
        1) Start the machine while holding down the Option-Apple-P-R keys

        2) Wait until you hear the 3rd startup chime, then let go of the keys and let the machine boot up.

        If you continue to experience issues please contact our tech support

        • Jose says:

          Thank you very much but I still have a doubt.

          Do you mean trying an SMC and PRAM reset before installing the new memory or once it’s installed.

          Thank you.

    7. Elvis Vincent says:

      Will it bugger my MacBook (late 2008) if I use the faster RAM, 1333 vs 1066, and is there any real value to the faster RAM if the bus speed bottlenecks things at 1066? I am running OS-X 10.9.1.


      Elvis Vincent

      • OWC Ben says:

        We only offer and support 1066Mhz memory for the Late ’08 MacBooks. There is no benefit to running 1333Mhz memory even though it is theoretically possible to use it.

    8. Russ says:

      Sorry if already Asked & Answered, but is faster RAM supported, such as PC3-12800 SODIMMs? I’ve generally not had an issue using faster RAM in desktops since the Bus will make them operate at slower speed ratings anyway. And if in this case those matched sticks won’t work, what is the fastest RAM that will function properly?

      • OWC Ben says:

        We only offer and support 1066Mhz memory for the Late ’08 MacBooks. All speeds of DDR3 are suppose to be backwards compatible with each other, so theoretically 1333Mhz memory would down clock to the proper 1066Mhz speed. Doing this would be of no benefit to the performance of the computer and only leaves the door open for issues to be created.

        • Phillip Knoll says:

          I tried replacing RAM in this machine using some 1333MHz DDR3 (Corsair) and it failed… but that RAM also failed in a MacBookPro6,2 as well as MacBookPRo5,1. Your mileage may vary. It definitely worked with Samsung 1066MHz PC8500S DDR3

          • Paavo Rissanen says:

            MacBook5,1 (Aluminum Unibody Late 2008) is especially very specific about what kind of RAM module is placed in the first RAM slot – it must always be exactly the same as is in the specs by Apple. In the other slot can be almost anything including 1333MHz RAM modules.

    9. Nick says:

      Awesome post!

      Running Mavericks on a late 2008 Macbook 5,1 2Ghz

      Boot ROM is MB51.007D.B00.

      Does it need to be upgraded in order to use 8GB RAM? In the article you say it should be MBP51.007E.B05, but the current version on the applie site is listed as MB51.007D.003.


      • OWC Michael says:

        It is the difference between MacBook & MacBook Pro that is causing the confusion here:
        MBP51.007E.B05 is the correct version for For MacBook Pro models (MacBookPro5,1).
        MacBooks with a Model ID of MacBook5,1 should have a Boot ROM version of MB51.007D.B03 as listed on Apple’s site.

      • Dith says:

        Hey Nick,

        How is Maverick running on your ancient Macbook? I have the same awesome model and looking to see if I should upgrade to maverick or stay with snow leopard. Also did you ever add that 8gb of ram and if so how is that working for ya? Also looking to upgrade in this department too. Thanks for your help much appreciated.

    10. zain says:

      can this mac run with 8gb ram
      Model Name: MacBook
      Model Identifier: MacBook5,1
      Processor Name: Intel Core 2 Duo
      Processor Speed: 2 GHz
      Number of Processors: 1
      Total Number of Cores: 2
      L2 Cache: 3 MB
      Memory: 4 GB
      Bus Speed: 1.07 GHz
      Boot ROM Version: MB51.007D.B03
      SMC Version (system): 1.40f2
      Serial Number (system): W8911GYV7WU
      Hardware UUID: 90A24162-9082-549C-A35E-7135586796F4
      Sudden Motion Sensor:
      State: Enabled

    11. Gandalf says:

      Thanks for making this clear. I’m a tech power user, but we get into ROM versions and you start to lose me. The flow chart at the end was exactly what I needed. I saw that I have MacBook4,1 and that settled it: 4GB is the max for me. Good work guys! I guess I’ll be getting a whole new system. Shucks! My disappointment is indescribable!

    12. markov says:

      these are my features of my macbook running 10.9.

      Model Name: MacBook
      Model Identifier: MacBook5,1
      Processor Name: Intel Core 2 Duo
      Processor Speed: 2.4 GHz
      Number of Processors: 1
      Total Number of Cores: 2
      L2 Cache: 3 MB
      Memory: 2 GB
      Bus Speed: 1.07 GHz
      Boot ROM Version: MB51.007D.B03
      SMC Version (system): 1.32f8

      can upgrade to 8GB?

      • OWC Jarrod says:

        Your model of MacBook is fully certified for 8GB of memory

        • markov says:

          Hello and thank you for your answer,

          by your message i undestand that i don’t need any extra firmware update to make the 8GB right?


          • OWC Jarrod says:

            That is correct. No firmware update is needed for your model.

            • Mac Carter says:


              I have exactly the same late 2008 Macbook as “Markov” and it has the updated firmware (Boot ROM Version: MB51.007D.B03). He asked if he could upgrade to 8GB Ram and you said YES on 12/17/13 — no need to upgrade the firmware. That is very encouraging.

              I currently have 6GB ram in my laptop and would like to boost it to 8GB. My question is, can I replace the current 2GB chip with a 4GB chip that was used in my mid-2012 Macbook Pro. I bought this 4GB chip from OWC quite some time ago and have recently upgraded to 16GB. So, I have two 4GB chips available. Both are DDR3 SDRAM chips.

      • Chewbacca says:

        Hi there,

        my wife’s Unibody Macbook 5,1 is running following setup:

        Boot-ROM-Version: MB51.007D.B03
        SMC-Version (System): 1.32f8

        Software OS X 10.9.1 (13B42)

        It really just has 2 Gigs of RAM, I just tested the 4 Gigs out of my Windows Laptop.

        So system wise I should be good to go. Is there anyway of determening if I habe the “too early” or the late EFI version?

        I will order RAM soon, just would like to know if I will habe to fiddle with the system more than that.

        Thanx to all.


    13. Tony says:


      I decided to upgrade the 2x 2GB memory. 10.9 Maverick seems to be really slowing down my MacBook… I purchased 8GB DDR3-1600 and got to work. Installing the sticks was easy, but after piecing everything back together and booting up, I got 3 beeps pretty much instantly. Switched the 2 4GB sticks around, no success. Running 1 stick at a time would not work either.

      I’ve tried several combinations and I found that the 4GB would not work in BANK 0/DIMM1, only in BANK 0/DIMM0. So I have now set up the original 2GB in BANK 0/DIMM1, and the 4GB in BANK 0/DIMM0. Resulting in 6GB.

      Any thoughts on what might be the problem? If I switch back to 2x 2GB there are no issues with either of the banks.

      Macbook5,1 (2008 Late)
      Intel Core 2 Duo
      2 GHz
      6GB RAM (1x 2GB original Hynix & 1x 4GB DDR3-1600)
      Boot ROM MB51.007D.B03
      Running OSX 10.9

      • OWC Larry says:

        I’m going to guess that the memory isn’t from OWC – Looking at the speed of the memory you purchased, that’s probably part of the problem and there are other differences we make as well in terms of ensuring the right compatibility for our MAXRam certified upgrades.

        This page has the correct memory for your 5,1 model:

        The maximum is 8GB for that system – so 16GB isn’t an option – nor is 10GB or 12GB with mixed… 8GB MAX

        right now you have a proper spec 2GB module and the system is slaving the program off of it when you have the other 4GB installed along with. The 4GB modules you have are not correct for it.

        Best solution – return what you bought and get a proper 8GB kit 4GB x 2 from the link above and you’ll be at 8GB and sailing smooth. :)

      • Juan says:

        I was just wondering if their suggestion to get their RAM (OWC) worked for you?

    14. Todd says:

      I’m having the same issue as Eathan Bell:

      Model Name: MacBook
      Model Identifier: MacBook5,1
      Processor Name: Intel Core 2 Duo
      Processor Speed: 2 GHz
      Number of Processors: 1
      Total Number of Cores: 2
      L2 Cache: 3 MB
      Memory: 4 GB
      Bus Speed: 1.07 GHz
      Boot ROM Version: MB51.007D.B03
      SMC Version (system): 1.32f8

      When I attempt to install, I get “Your computer does not need this update”.

      Has anyone tried this on 10.9 without having done the EFI update? Success?

    15. Chris Randall says:

      @Eathan Bell, maybe you didn’t read this entire article, but you need to update your boot rom. Its 4 versions to old. Here is the latest version http://support.apple.com/kb/DL1502

      Then I would do a clean install to Mac OS 10.9 Mavericks when it comes out later today.

      And finally after a fresh install do a restore from a Time Machine backup.

    16. OWC Ben M says:

      Having an older OS then Snow Leopard will not affect the ability to install 8GB of memory. It sounds like you have some defective memory. I would recommend running Apple Hardware Test or Rember to see if the 8gb of memory tests defective.

      • Eathan Bell says:

        Thanks for the suggestion. I went into Single User mode, did a memtest with both sticks in, and got some “Data Mismatch” errors. After consulting Googe, someone on another forum mentioned to do a memtest with each stick at a time. I did just that, and found out that only the one stick had the errors. For now I am using the working 4GB stick and an older 2GB stick, and it works just fine. I know it’s recommended that you upgrade both sticks at a time, but for now this will do. Thanks for the help. :D

        Btw, is that other stick just unusable, or is there anyway to recover it?

    17. Eathan Bell says:

      Quick question, am I able to still do this if I have a newer OS clean installed? Meaning Snow Leopard was not on the hard drive before install. Mountain Lion in my case.

      My specs:

      Intel Core 2 Duo
      2 GHz
      4GB RAM
      Boot ROM MB51.007D.B03

      I bought some Mushkin Apple memory, 8GB(4GBx2) of course as the article is regarding. Installing it worked fine, no three beeping as others have had… but after a while I noticed slow downs and some even odder things, like files seemingly disappearing and programs not opening because of missing files. This was about a week after using it. I put back in the 4GB RAM and everything is fine now. Is this because I didn’t have something installed that Snow Leopard would have had, and Mountain Lion doesn’t have now? Or is it just because I maybe need to wipe my hard drive, install a fresh OS, and go from there? Should I try to just run 6GB of RAM?

      Also, resetting the PRAM did nothing.

      Thanks in advance for any advice.

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