Hi There, I was told that the 512mb dimm of the correct size/density didn't exist at the time of the rev A iBooks, so they are listed as max 288 - 32 built in+ a 256 (Tang/ Blue 300s) or 320 - 64 built in + a 256 for the 366 (graphite) version, but they will see the 512s made now. I'm guessing that you are correct that you need the firmware update. I picked up a used 366 graphite, and have ordered a 512 Dimm for it, but haven't got it yet. Bob Wilson Boston, Mass In a message dated 1/13/03 6:42:12 PM, danfarley at mac.com writes: >>> I have a Blueberry clamshell ibook. I have a 256mb dimm in the top >>> slot, and according to mac, that's all I can install there. If I were >>> to say drop in a 512mb dimm, would it recognize the additional memory? > >I just did that (installed a 512) and now my Blueberry (rev 1 with 32 MB >of >ram) now indicates 544. I'm not sure - but I do think you need to have >the >latest and greatest firmware installed. Easily done via software update. > >Dan