This question is directly relevant to my failing attempts to upgrade the RAM in a Late 2009 White Unibody MacBook (MacBook6,1) to 8GB, and the question may be better asked in that context.

It is widely referenced (most authoritatively on everymac.com) that this model can support 8GB (despite Apple saying the max is 4GB), but in the "System Information: Hardware Overview" screenshots of every successful upgrade, the Boot ROM Version is shown as MB61.00C8.B02 while mine is at MB61.00C8.B00. While it's possible that I got bad RAM, I'm wondering if the earlier firmware version doesn't support 8GB. I did find one other person on a forum with the B00 firmware having the same problem I am ("3 beeps and won't boot with the RAM installed"), but no resolution; he did RMA his RAM at least once.

Apple doesn't show any firmware updates at all for the MacBook6,1 model, so there's nothing official for me to try and re-flash.

Has anyone managed to get 8GB working under B00, or upgrade it to B02?

  • Interestingly, I just installed 2x2GB SODIMMs taken from my Mac Mini (when I upgraded to 8GB) into the MacBook. They work, and are seen by the MacBook with a speed of 1333 Mhz (as in the Mini), despite the laptop being listed as supporting / needing 1066 Mhz RAM. I guess an RMA is in order...
    – Rob Walsh
    Jul 9, 2013 at 16:53
  • Just tried 8GB, but in a B02. Got three beeps and no boot here as well. Corsair MacMemory CMSA4GX3M1A1333C9 Best guess: Mine is a 2009 MacBook6.1 (not the 2010 model); while it is listed as supporting 6GB when 2x4GB is installed; it probably does not run with 1333 SPD timings?
    – user56918
    Sep 11, 2013 at 21:18

2 Answers 2


My 6,1 B02 has 8G RAM and works fine. It also runs in 64 bit mode, which I enabled some time ago with the help of a simple hack (can't remember all the details, just google macbook, 64-bit, boot.efi, boot64.efi).

You could try to manually upgrade your firmware with the fw-upgrade of the macbook pro 5,5. It has been done successfully by several people:


BTW: By doing this, you will probably also fix the MCP79 bug that makes MCP79 negotiate SATA1 with newer SATA3 drives (instead of SATA2).

System Profiler:

screenshot of MacBook's System Profiler

Note, that with 8G RAM, hibernation ("safe sleep"?) will make WindowServer crash if you're still running 10.6 (Snow Leopard).


How to install the firmware from a MacBook Pro "Core 2 Duo" 2.26 13" onto a MacBook "Core 2 Duo" 2.26 13" (Uni/Late 09) [Action should correct SATA speed issues and maybe RAM issues]:

  1. Do a clean install of Yosemite (this should be optional, but it never hurts to start clean)
  2. Download http://support.apple.com/kb/DL853 (MacBook Pro EFI Firmware Update 1.7)
  3. Install Pacifist: https://www.charlessoft.com/ (or whatever software you like using to extract files)
  4. Open Pacifist and then drag the MacBookProEFIUpdate.dmg into it
  5. Expand: Contents of MacBookProEFIUpdate.pkg -> Contents of MacBookProEFIUpdate.pkg -> Applications -> Utilities -> MacBook Pro EFI Firmware Update.app -> Contents -> Resources
  6. Drag MBP55_00AC_03B_LOCKED.scap to the Desktop
  7. Click the Extract button in Pacifist and enter your password if prompted and press OK (might need to enter your password twice)
  8. Quit Pacifist
  9. Click Go -> Utilities
  10. Open Terminal
  11. Type "cd Desktop" without the quotes and press Enter/Return
  12. Type "mv MBP55_00AC_03B_LOCKED.scap MB61_00C8_B02_LOCKED.scap" without the quotes and press Enter/Return
  13. Make sure your laptop is hooked up to a reliable power source
  14. Type "sudo bless -mount / -firmware MB61_00C8_B02_LOCKED.scap --recovery --verbose" without the quotes and press Enter/Return
  15. Type your password and press Enter/Return
  16. Restart your Mac (you should hear an angry beep, then see a black screen like nothing is happening for a good while, then a gray screen with a progress bar, and finally the Mac will reboot again)
  17. Once your Mac has booted, open your System Report and verify the update was successful (Should show the Model Identifier as a MacBookPro5,5)
  18. Have a drink!

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