A couple of weeks ago, Intel acknowledged reports that firmware updates for Spectre and Meltdown resulted in reboots and other stability issues. At the time, they still suggested that end-users should apply the patch regardless. They have since identified the cause and their recommendation has changed: OEMs, cloud service providers, system manufacturers, software vendors, and end users should stop deploying the firmware until a newer solution is released.
The new blog post also states that an early version of the updated patch has been created. Testing on the updated firmware started over the weekend, and it will be published shortly after that process has finished.
According to their security advisory, another patch that solved both Spectre 1 and Meltdown did not exhibit stability and reboot issues. This suggests that something went wrong with the Spectre 2 mitigation, which could be a fun course of speculation for tea-leaf readers to guess what went wrong in the patch. Ultimately, it doesn’t matter, though, because new code will be available soon.