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

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.

Related: See All Upgrades Compatible with Your Mac with My Upgrades Tool

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.

Related: Now is the time to upgrade your memory with OWC!

M. Chris Stevens
the authorOWC Chris S.
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  • Note that in addition to the listed models, MacBookEFIUpdate 1.4 allows a MacBook5,2 (Mid 2009) to use 8GB RAM. After update, the boot ROM version is MB52.088.B05.

    I should also mention that not all brands of DDR2 RAM will boot in a Mac. Some PC RAM isn’t recognized. If your Mac is beeping every 5 seconds, the RAM isn’t recognized, and your Mac thinks there is none installed. Buy RAM tested for Mac compatibility.

  • Hi, similar situation as Jhon here, but my mac is a A1286 late 2011 15 inch. Mac OS High Sierra 10.13.6 Boot ROM Version: . Downloaded the MacBook Pro EFI Firmware Update 1.8 but won’t install on the computer. any tips?

  • Hi guys!
    My MB 13, late 2008, runs OS X El Capitan, with boot ROM MB51.007D.B03.
    With 8gb the computer won’t turn on & beeps 3 times in succession.
    The EFI update for MB 5,1 won’t install on the computer, so I’m left thinking that I need to downgrade my OS?
    Any thoughts please about this?

  • Hello
    I have a Early 13 inch Macbook 4,1 – 2.1 Intel Core 2 Duo with 4 GB 667 MHz – my question will this firmware upgrade work in the Early model I have?

  • This article is really what I was looking for! Thank you! I am upgrading my daughter’s computer thanks to you!
    May I ask you a question: what about upgrading a MacBook Pro 2,2 (2006, A1211), Mac OS X 10.7.5, to 8GB of memory RAM? Or at least 4GB? The boot ROM is MBP22.00A5.B07GB. Is is worth it?
    Thanks for your help!

  • hello …

    how do I install an efi uodate on my new ssd ?

    when I start my mbp unibody it will show ( ? )
    with the alt key it will not show any thing ….

    after putting an efi file from a linux knoppix
    and alt > it will show a windows hdd …
    to put the pointer on
    and press

    then the screen goes black
    then after more then a minute
    a gray screen starts
    and the message >

    ” Remove data carrier
    restart: press any key ”

    can I copy the mac efi update 2.8
    directly in the > efi partion ?
    of this san disk 120gb ssd

    and how can I install a smd update ?
    before installing os 10.5.6


  • Late 2008 Macbook 5,1 MB51.007D.B03 SMC Version (system): 1.32f8. Installed 2 x 4GB Ram one slot reading and the other says empty. Reinstalled the 2 x 2 GB Ram both slots work fine. Am I missing something on installing the RAM to have 8GB?

  • I have an 08 15 inch MacBook Pro that I upgraded RAM to 8GB and installed a 480GB SSD. The 11 year old machine is very spry now. Boots up in 28 seconds and moves through applications swiftly. I use it as the media server for my home network. Got all my information and supplies from OWC/MacSales. They have kept ALL my Macs running for 11 years now.

  • I’m trying to update my firmware on MacBook 5.1, is there a way to do this? The download link on Apple doesn’t work.

  • Hi everyone; I have a MacBook Late 2008 with Boot ROM version of MB51.007D.B03 however when I download **For MacBooks (MacBook5,1) MacBook EFI Firmware Update 1.4** it says **This computer does not need this update.** What’s the problem you think? Thank you!

  • Have a late 2008 unibody Macbook with Boot ROM Version: MB51.007D.B03 and SMC 1.40f2. Would upgrading to 8 GB work here? And what would be the highest OSx that one can run it with for 8GB to work properly? The laptop is currently on 10.7.5 and I am hesitant upgrading it to 10.11 if 8 GB do not work on it. Which lower OSx version would support 8GB? Thanks for your help.

  • Hi there, I’ve been trying to do this for a while. I have a MB late 2008 with:
    Boot ROM Version: MB51.007D.B03
    SMC Version (system): 1.32f8
    And i’ve 2 4gb ram but it shows like i’ve only 2 2gb ram. I am funning osx 10.8.5 with and ssd and I would love to upgrade the osx, how can i fix this?
    thanx in advance.

  • After installing MacBook EFI Firmware Update 1.4, each time the computer is booted it displays a popup notification informing me that the firmware has been updated.
    Does anyone know how to disable this?

  • I just did it, now my MacBook 13 inch, Aluminum Late 2008, Processor 2 GHz intel core 2 Duo is showing the 8 GB 1067 MHz DDR3,
    it’s working.

    • sorry, can’t find an option to delete this. found the answer in the comments. just took some time as there are a number of them. there are claims that 1333mhz works. I ordered it and waiting for it to be delivered.

  • I’ve got an MBP unibody, late 2008, and it takes 8GB, no problem, in fact, it did back in 2010, before the update. I highly suggest that anyone with a model this old keeps a 10.6.8 partition, since anything newer runs INCREDIBLY slower. If you need support for newer apps, run 10.10.X, anything newer is WAY too slow. 10.9 is actually the slowest of all. Don’t even bother with Lion or Mountain Lion, and forget 10.11 and 10.12.

    I’m a bit confused by the article. My friend has a late 2008 Macbook 4,1. I read that Apple’s official specs say 4GB, and some other sources say 6. I know from years of experience that Apple always lowballs it. But, does article mean that it can indeed take 8? If i put in 8, and it doesn’t recognize all 8, will it just not boot, or will it run as if it only had 6?

  • So i have a aluminum body late 2008 macbook, model ID MacBook5,1 and Boot ROM version of MB51.007D.B03 but for some reason when i tried to upgrade to 8GB of ram my macbook won’t start i get an error msg and tries to restart again. any ideas on what the issue could be???

  • Hi there :)
    I just acquired a MBP 17″ A1261 2.5 Ghz 4Gb 250gb 1920×1200 10.11.5 OSX El Capitan.
    I’m new to all this and would really appreciate your help. :) I will mainly use it to move my daughter’s choir performances, church worship (4 years’ worth) from the cloud to cd’s for grandparents, and pictures of trips from the cloud to cd – and create family videos and watching movies/videos with family aside from work and adding music. Before I start putting anything on it, should I upgrade it to 6gb or 8gb? How should I do it – where should I get help? Also – 250gb might not be enough to hold all of these – so should I upgrade that as well to 500gb? Will that slow the computer down? How much does all of these cost?
    Thank you so much for your help!!! I need some guidance and help :) !

    • Hi, Caroline. To get the best performance from your Mac, we highly recommend installing the maximum amount compatible with your model. And if you would like a large amount of storage that will bring better performance to your Mac, an OWC SSD will do wonders for your Mac. Our My Upgrades tool will show you exactly which upgrades are compatible with your Mac. It can be found here: https://eshop.macsales.com/upgrades/. You can also reach out to our helpful customer service team for additional support. Thanks!

  • Hardware Overview:
    Model Name: MacBook
    Model Identifier: MacBook 5,2
    Processor Name: Intel Core 2 Duo
    Processor Speed: 2GHz
    Number of Processors: 1
    Total Number of Cores: 2
    L2 Cache: 3 MB
    Memory: 2 GB
    Bus Speed: 1.07 GHz
    Boot ROM Version: MB52.0088.B05 (EFI 1.4)
    SMC Version (System): 1.38f5
    Serial Number: W8915F934R1
    Hardware UUUID: 86402231-7C6A-578E-A7D8-00ABABE4F83C
    Sudden Motion Sensor:
    State: Enabled

    OSX 10.10.X (Yosemite)

    Can I upgrade from 2 GB to 8 GB of Memory or limit myself to 6 GB? Seems to be two different school of thought as to what the max memory should be for the MacBook 5,2.

  • Loved this article.
    I’ve had a 2008 MBP since new and love it.
    Installed SL over 10.5.5 Leopard just to use certain connectivity and think it’s great.
    The old stock RAM is getting wonky with SBOD and suspect the RAM.
    The firmware, as with all apple products, is the key.
    I am ordering 2x4g Crucial and revamp a classic oldie lapper.
    Thanks again for the writeup and comments here..

  • Hi, I have a MBP version 5,1 running 10.11.6 with Boot ROM Version: MBP51.007E.B06. I can only upgrade the ram to 6 GB, 2gb in one slot and 4gb in another. When I try 8gb it beeps and won’t boot. What is the reason? Is it the make of RAM?

      • I have the same issue as Bevis, but my macbook is the MB 5,1 with the boot ROM MB51.007D.B03 and running El Capitan.
        I can have the 2G+4GB but not the 4GB+4GB.
        Did you managed to fixe it?

        • same issue as Francisco. I have the late 2008 unibody, running MB51.007D.B03 and it will only let me use 6GB of RAM, 2 in the top slot, 4 in the bottom. Ram is Crucial 4GB DDR3 1067 and it just beeps when I try to boot with 8GB installed. Not sure if 6GB is faster than the 4GB since its mismatched.

          • Also should note im running OS X El Captain version 10.11.6
            From the looks of other comments on page 8, this is likely the issue and I haven’t seen a fix noted in past responses. Might need to look into downgrading the OS and trying again

  • Thank you for the information to upgrade to 8 GB. I have a late 2008 aluminum macbook. It has the same Boot Rom version you stated in your great article… I’m running “lion” 10.7.5. Do I need to upgrade to El Capital first? Or I can I upload the 8GB with “Lion” as of now. Planning to upgrade to El Capitan (or newer versions that can support this laptop) – but should I upgrade the GB’s now or do suggest upgrading to El Capital prior to installing the 8 GB? Thank you so much for any feedback you can give. Lastly, may be a stupid question, but do I need to check for the EFI firmware? I think that’s the Boot Ram I now have that you suggest prior to installing 8GB. Hope I”m making sense. Thank you again!

    • Thank you so much for your questions. As you have the MacBook 5,1, have matched the Boot ROM version and running 10.6.8 or later you will be able to upgrade to 8GBs without any problems. We suggest that you upgrade the RAM before upgrading to El Capitan.

      Please let us know if you have any further questions.

  • Hi,

    I’ve got a MacBook 5,1 2008 Late. 2GHz with 4gb RAM. Boot ROM Version: MB51.007D.B03.

    I’m running El Capitan.

    If I try to install the 2.8 firmware it says “The computer does not need this update”

    Can I still put 8gb ram into my macbook? Will it work?


    • Thank you for your question! You will still be able to upgrade to 8GBs of RAM!

      Please let is know if you have any further questions.

  • Hi I have a 13 inch Max pr (mid 2009) with 4GB 1067 MHz DDR3. I have just updated the OS to 10.11.6. Can I upgrade to 8GB RAM? If so which prodcut would I need to do this? Could i just get another 4GB such as this: macupgrades.co.uk/store/product_info.php?products_id=953

    Many thanks

  • Hi,I have followed your instructions but it doesn’t work for me. The laptop doesn’t load, it switches front light but it doesn’t goes on. If you can help me. My version is 10.11.6 Thanks

  • Hey! Nice article. I just pulled my old macbook out of storage and am refurbishing it to use as a music interface. I had all this set up already and am running 8GB RAM, but I stayed on 10.6.6 because at the time when I was doing this upgrade I was told that if I go PAST this that the upgrade would cease to function properly and I would go back down to 4-6GB. Is this true? I really want to upgrade this laptop for use with newer programs, but I don’t want to lose my 8GB, Obviously. And on another note, what’s the best(highest) OS I should go too with this 5,1 Macbook. Thanks.

    • I have asked efficiently, becauseI have read that I can install 2x4GB, but if more than 6GB is accessed, performance drops of a cliff…
      So…. Is 5,2 OK for 8GB, or should I go to 6GB?

      • Thank you so much for your question. In the MacBook 5,2 the maximum amount of RAM you will be able to use is 6GBs. We would not recommend going any higher.

        Let us know if you have any further questions.

  • So my mac meets all of the above criteria. Can someone direct me to the precise product I need to max out my RAM? From what I can see I need 2 x 4Gb. Thanks a mil. Great article. very clear for those of use with novice tech literacy.

  • I have a [Apple MacBook “Core 2 Duo” 2.0 13″ (Unibody)] (i checked with EveryMac). Currently it has 2x2GB, which works. The OS version is 10.11 (El Capitan). When I try to use a Kingston KVR16LS11/4 [https://www.kingston.com/dataSheets/KVR16LS11_4.pdf] (4GB), the Mac emits [3 successive tones, a 5 second pause (repeating)]. System Profiler/Boot ROM version is MB51.007D.B03.

  • hi, I have a MacBook5,1, with 4G ram and a500 SSD, the numbers I get are: MB51.007D.B03.
    can I install 4 more Gs of RAM? I tried installing the EFI update but i get a message saying that my computer has no need of this update..

  • I’m trying to figure out if the MBP 15 inch I have is able to handle the 8 GB upgrade. The Boot ROM version is MBP53.00AC.B03. This appears to be the latest version available. Will this still work?

    • Thank you so much for your question! Your 15″ MacBook Pro will be compatible with 8GBs of RAM with Boot ROM version MBP53.00AC.B03!!

  • This blog is awesome!.
    I am on a late 2008 10.9.5 with 2+2ram and firmware MB51.007D.B03
    I am giving this girl a revival. New SSD and maybe new batt.
    On firmware update Feb 28, 2012 I get Alert “This software is not supported on your system. ”

    The philosophical question : Should I buy 4+4 ram together with new SDD drive and cruise in 10.9 for eternity?

    • Hi, Agustin! Thanks for the kind words. And you will definitely be able to extend the life of your late 2008 MacBook with more memory, an SSD, and a new battery. To help find the compatible upgrades for you, I suggest using our MyOWC search. There you can find the proper SSD, RAM and battery for your MacBook model. And if you have any questions, feel free to contact our https://eshop.macsales.com/Service/

  • I’m on El Capitan, late 2008 with MB51.0073.B06 ROM. Start-up freezes at around three-quarter of the bar (apple logo load screen) when I use two corsair ram units (2x4gb). When I use 1x4gb, 1x1gb it works just fine. Do you know how to fix this?

    • Same thing happened to me… I updated the ROM to the version that supports 8GB (I believe MB51.007D.B03)- it worked thereafter. This is for the Macbook 5,1 – aluminum version (late 2008)

  • With the last version of El Capitan my macbook only uses max 6GB of the 8GB avaliables inside. This only happen with the last version, since 2012 I´ve been using those 8GB…
    Anybody knows what happened??
    Thanksn in advance

    • Did you ever figure out a fix?

      I’m on El Capitan, MBP Late 2008 with MBP51.007D.B06 ROM and 8gb I get 3 consecutive beeps. 6gb works just fine.
      I’ve reseated RAM, checked both new sticks, PRAM reset, SMC Reset, etc.

      • I have a MB aluminium late 2008 (MB51.007D.B03).
        I have 8GB since 2012 but my computer only uses 6 of them since last El Capitan update, nothing about beeps…

    • Having the same issue here. 6gb works just fine , but once I insert 8gb I get the triple beeps.

  • I tried upgrading after downloading the firmware update to my MacBooks (MacBook5,1) but, it reads “this computer does not require this update”, event hough my current firmware is MB51.007D.B03 and I am running on el capitan.

  • Hello,
    My Boot Rom version is MB51.007D.B03. But when I attempt to install the update to my macbook(macbook5,1), a windows pops up that states “This computer does not need this update”. I am currently running el capitan version 10.11.15.

  • Good Day to you, was planning to sell my Macbook til i saw this thread, might be keeping it for a while for now, here’s my specs:

    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: 4 GB
    Bus Speed: 1.07 GHz
    Boot ROM Version: MB51.007D.B03
    SMC Version (system): 1.32f8

    Kindly let me know if i can install 8gb RAM on my baby.. Cheers.

  • Hello,
    I have MacBook 13 inch Aluminium Lte 2008, 2,4 Ghz and boot rom version MB51.007D.B03 / macbook5,1.
    It is possible to install 8GB ram on this macbook?

  • Hi there,

    you wrote:

    “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”

    So how do I know, if I have the old code of the >>first<< EFI-Update 1.4, since you say both the first update and the new EFI-Update 1.4 from 08.12.2009 do both show ROM MB51.007D.B03 for my MacBook5,1 ?

    I don't know, if the previous owner of this MacBook had done the first EFI-Update like you did, which only addressed 6GB?

    Here my specs:
    – MacBook5,1
    – 2 GHz
    – 13"
    – MB51.007D.B03
    – SMC: 1.32f8

    Thanks for your help

    • Hello Spoogy,

      Your Boot ROM Version is correct and compatible! You’re already able to install the 8GB without any problems and don’t need to perform further updates.

      If you have any further questions, please contact our Technical Support Team!

    • Hello Spoogy,

      Your Boot ROM Version is correct and compatible! You’re already able to install the 8GB without any problems and don’t need to perform further updates.

      If you have any further questions, please feel free to contact our Technical Support Team!

      • Hi Dyllon, thanks for your reply.

        But I wanted to know something else :-)

        This article said, that they had previously done the first EFI update 1.4 and could only handle 6 GB, even that the ROM Version showed MB51.007D.B03.
        Only after they manually did the EFI update 1.4 again, which was silently updated by Apple, they could handle the 8 GB, event the ROM Version still showed MB51.007D.B03.

        So how can I know, If I got the old MB51.007D.B03 or the new MB51.007D.B03 ?

        I hope I could explain it clearly.
        Thanks for your help!

        • Hello Spoogy,

          We are very sorry for any confusion that has been caused. If you have Boot ROM version MB51.007D.B03, you will have the correct version for the 8GB upgrade kit. In the article when it states there was an older and a newer version that you can not tell the difference between, this was before Boot ROM version MB51.007D.B03.

          To double check you can use the most up to date MacBook EFI Firmware Update 1.4. If this update does not work and states it is not needed, you will have assured that it is the correct one.

          Please contact us if you have any further questions! We will be happy to help!

  • I have a late 2008 MacBook 5,1; 2.0 GHz; 2 GB; Boot Rom MB51.007D.B03. I am running OS X 10.5.8. I want to install 8 GBs RAM, and then start process of upgrading to latest version of OS X El Capitan. Can you please advise if this is an OK order to make the transition run smoothly?: 1. Upgrade to Snow Leopard, 2. Install 8 GBs, 3. Upgrade to El Capitan. Also, can you please advise on an SSD and where that potentially fits into this scenario. Thanks!

  • I have a macbook same late 2008 aluminium version but i need to know the maximum speed and Hertz of memory i bought some hyperX but they don’t work but i have more just need specs i am already running OS 10.9.5 on A SSD Hard drive need help to maximum memory