Hi this is my first post, I just bought the new Macbook (MB402LL/B) from BestBuy, where I work. First, the title is a little misleading. I know the memory is upgradeable... But, on the box it says expandable up to 4 GB - which I am leaning is incorrect. I work at the Geek Squad and am a Computer Engineer working with Solaris and various different hardware platforms and OS's --- Im hardly a newb and have tried several things to get my new Macbook to accept the total 4GB it advertises. So your help would be appreciated. So I purchased two 2GB Kingston certified PC2 5300 apple memory chips (4GB total). I installed both, and immediately got three beep codes. My troubleshooting and results: 1. I reseated the memory (must be dozens of times) with no resolution. 2. I removed one memory chip, the system booted up fine. Thought I might have a bad memory chip... So I removed the now working chip with the one I previously installed (swapped them) The system booted up fine... 3. Reinstalled the previously working chip and attempted reseating it again - no joy. 4. Replaced the memory chips alltogether - no joy. 5. Interchanged one memory chip between both chip modules/slot... both slots worked with one 2GB chip in each. Doesnt appear to be the mobo.. 6. Reinstalled a single 512MB chip (factory chip) with 2GB chip (total of 2.5GB) - System boots fine. How do I get to 4GB? I didn't see any sort of firmware update with the Mac Updates.. has anyone else had this problem?