CyanogenMod has decided to drop support for the Samsung Vibrant after discovering that the phone can't dial 911 running the crew's own open-source Android build.
The CyanogenMod team relayed the bad news on its own forum earlier this week:
We are no longer supporting the Vibrant due to the inability to dial 911. We consider the issues related to this unresolvable without source code from Samsung related to the Radio interface layer and its interactions with the Audio layers and have taken the decision to no longer support this. We apologize for the inconvenience and strongly suggest that Vibrant users use a Samsung ROM due to the 911 issues with any ROMs based on open source code.
CyanogenMod is know for creating custom Android builds for different mobile devices. Such custom builds, or ROMs, can often beef up the speed and performance of the device, remove certain restrictions, and allow users to tap into more features. CyanogenMod's own custom ROM supports a variety of Android devices, usually without too much trouble.
But clearly the inability to dial 911 in the event of an emergency should be a deal breaker for any Vibrant owner looking to run CM's open-source custom build. Beyond the Vibrant, the problem has also affected the Samsung Epic 4G, though a new custom build described on the XDA Developers forum has reportedly fixed the 911 issue with that particular phone.