Ok, so first you go out there and buy incompatible ram memory to upgrade your macbook pro. Yeah, don’t even look will the 1333 Mhz clock speed work in this computer which comes with 1066 Mhz by default. Of course you can assume that even if the 1066 Mhz is the maximum speed, EFI will just automatically downclock speed from 1333 Mhz to 1066 Mhz and everything will be ok. Right? (Spoiler: NOT!)
Then, you open up the macbook pro and replace those ugly little old modules with the shiny big new ones, close it, tighten the screws and happily press the power on button.
You hear the familiar startup sound, and here it comes the apple boot screen! Everything is going as it should. Still apple boot screen… Did the loading circle just stop moving?!
Then, you realize something went wrong. It’s too late now, I know… Then you find out everything you needed to know in the first place, before you actually bought the memory.
Macbook Pro 13 Mid 2010 is one of the very rare models, which will not boot with the 1333 Mhz memory. Almost like all the other will do it, including older models, mac minis, iMacs and so on… Shit! Only my model won’t work with this memory!
Then, you start to think, there’s got to be a way… And you start researching…
You try changing place of modules and all the possible combinations with old and new memory and finally find out that new memory only works in combination with the old. It’s because old memory is working on 1066 Mhz, and EFI Firmware automatically downclock the new one to this speed. If you put only the new memory, one or two, never mind, EFI doesn’t do anything, it doesn’t try to put the speed down. And you don’t want to end up using 6GB of Ram when you have 8GB!
You try everything you find on forums, that may even remotely be kind of your problem. You verify disk, permissions, repair everything, reset PRAM/NVRAM, SMC, turn on Verbose Mode, inspecting every line of it and stuff, but nothing helps. It’s still the same.
Then, you accidentally find out that computer will normally boot into safe mode. Wtf?! It reads all the 8GB of memory and says it’s speed is 1333 Mhz. So then you think you got something. (Spoiler: but really you don’t)
After many tries of everything, you decide to reinstall your 10.6.6 OSX. You was saving that as a last resort, but here we go…
Fresh OSX installation (10.6.3) is booting up, and it’s in! Welcome on many languages is here! Yeeeeeey! It’s working! Then you start to download and install all the updates, and then, but only then, you can go to sleep because you work tomorrow, and it’s very late. Installation of updates is finished and computer is restarting, apple logo comes again. It’s still here… It doesn’t go away… You feel sad. And sleepy. But your work isn’t done yet.
Then you do all of the stuff you already done again, and then you go to sleep because you have no more ideas. You have to sleep sometimes!
Day 2
You’re on work, but all you want to know right now is why is this fucking happening?! There’s got to be a way! And there is, and here it is…
You find out that there is some windows software called Thaiphoon Burner and it’s free alternative SPDTool that are able to modify the SPD (a small non volatile flash, located on the memory, containing information about it) if the EPROM is not protected (depends of memory manufacturer). So theoretically you could change setting of your ram memory that it works on 1066 Mhz, like the opposite of overclocking. Great, you gotta try that one! :)
So you download both programs, and then you realize you don’t have stupid windows on your laptop. And you need it there, not like a virtual machine, but on a boot camp partition, a real thing. Oh shit. So you burn that damn Windows XP image that you found somewhere in forgotten folders (choose XP instead of Win7, just to get it done as quick as possible and without fear of incompatible programs and stuff). Start Boot Camp Assistant and after second step (download windows support shit) something already goes wrong… Saving downloaded drivers doesn’t work in any way (burn or copy to hdd). After a little research you find out it’s a bug in the last version of everything and that’s it… You skip that step and continue with making partition for windows. This operation fails in the middle, then you do research again, free up some hard disk space, repair permissions, restart and what not, and try again. It works this time. Partition is created. You start XP installation from CD, and then you feel the pain. You know, that old blue & yellow DOS interface? God, it hurts. You survive that somehow, after files are copied to disk, restart comes along and of course, disk error, can’t go on. So you start installation again from the beginning, this time with slow FAT format included, and windows is finally installed.
Then, you put one old and one new module mixed, so it can work.
Ok, let’s first try the free version of SPD modify software, SPDTool. It shows some error on startup, and nothing looks like it’s working. Then you find out it’s last update was in 2007. Next!
You start Thaiphoon Burner, and it looks like it’s reading the memory. OMG, Finally! :)

Firstly, you create some backups of original SPD just in case.
The rest is easy. You read the correct slot, go to editor, change “Min SDRAM Cycle Time from 12 to 15, and with that, Clock Freq changes from 666.67 (1333) Mhz to 533.33 (1066) Mhz.

You write the changes to SPD on the memory, and you’re done. One of the new modules is now working on 1066 Mhz because it’s set like that on the memory itself.

Now, you put the other new module with this one, and EFI should automatically downclock that one to 1066 Mhz, because of the lower speed of the first one.
Finally, what’s is gonna be?
It just works! :)

You’re ready to delete boot camp partition and continue your life like nothing happened, but with more ram memory, like you need it for real…
Oh, how much time is it?! I’m still at fucking work! Check this link. I’m off!