Hello! This is a quick clarification about support for CDMA devices.
For various technical reasons, recent CDMA Android devices implement core telephony functionality in .apk files provided in binary form by the carriers. To function correctly, these .apk files must be signed by the so-called "platform" key. However, when an individual creates a custom build from the AOSP source code, they don't use the same signing key as these CDMA flies were signed with.
The result is that these files don't work properly, and pure AOSP builds running on these devices can't place calls, access mobile data, and so on. Because we aim to make sure that we are as clear as possible about the degree of support that devices have, we updated the docs over at source.android.com to reflect this reality.
We will still make available as many as possible of the closed-source binaries for these devices, and Nexus devices will continue to have unlockable bootloaders. And, of course, GSM/HSPA+ devices are still supported, as are any other devices we're able to support. We've simply updated the documentation to be clearer about the current extent of CDMA support.
We are of course always working to improve support, and we'll keep everyone updated as we make improvements. Thanks as always for your interest in AOSP!