http://www.raspberrypi.org/archives/2180
Update: Those of you lucky enough to receive a 512MB Pi this morning can download updated firmware here. For example, download arm384_start.elf and rename it to start.elf on /boot partition. You will then have a 384M/128M memory split.
One of the most common suggestions we’ve heard since launch is that we should produce a more expensive “Model C” version of Raspberry Pi with extra RAM. This would be useful for people who want to use the Pi as a general-purpose computer, with multiple large applications running concurrently, and would enable some interesting embedded use cases (particularly using Java) which are slightly too heavyweight to fit comfortably in 256MB.
The downside of this suggestion for us is that we’re very attached to $35 as our highest price point. With this in mind, we’re pleased to announce that from today all Model B Raspberry Pis will ship with 512MB of RAM as standard. If you have an outstanding order with either distributor, you will receive the upgraded device in place of the 256MB version you ordered. Units should start arriving in customers’ hands today, and we will be making a firmware upgrade available in the next couple of days to enable access to the additional memory.
I’d like to thank our partners, RS Components and element14/Premier Farnell, and the suppliers, particularly Samsung, Sony and Broadcom, for all their help in delivering a smooth transition to the 512MB. I’m looking forward to seeing what you all get up to with your shiny new Pis.