release for 4-Model-B support is imminent. we had previously released an image to support the new Pi, but became aware of an issue with the serial port where the OS version required to support 4MB was not interacting with the data transfer from the MCU over all time well enough to meet our quality standards.
consequently, the image supporting 4MB was replaced with the previous image that does not provide support for 4MB versions of the Pi. in the intervening time we have been working to find a solution to this problem and after digging very deep into the OS have identified a solution and have been in the process of testing this to confirm its veracity. testing is nearing completion and once certified, we will again update the image and make an announcement.
in the meantime, you will either have to use a prior version of Pi, if you happen to have one, or wait for the release of the updated image.
apologies for the delay, the update to the new Pi model has turned out to be more issue-laden than we would have liked. but since we have a dependency on a computer made by another company, this is a fact of life we can’t avoid.