Sometimes the cure is worse than the disease. Just ask the affected users of older AMD systems who had their PCs bricked after downloading and installing a Windows update that was supposed to protect them from Meltdown and Spectre. It is not just Windows users who are suffering, either. Some Ubuntu Xenial 16.04 users also report that the latest update for their OS has rendered their system unable to boot.
"I just ran an update on my Ubuntu Mate 16.04 system, which updated the kernel to 4.4.0-108. (I don't know if this version has changes to mitigate the recently-discovered Intel security flaws.) What happened afterwards is at boot time is the system locked up hard just as the graphical bootup screen attempts to initialize. The CPU is a Core i5-3570K using built-in graphics," a user stated on Ubuntu's community forum.
Others quickly chimed in with similar complaints on a range of systems, including a setup with a Core i5-3570K processor and GeForce GTX 760 graphics card, and an older laptop powered by an AMD Turion II X2 CPU.
"Yep - same here— did update and lockup at boot screen [with an] Intel NUC Celeron CPU 847 using onboard graphics," another user posted.
Canonical began pushing out the update to deal with Meltdown, and possibly Spectre, though the related security notice (USN-3522-1) only mentions the former. Between the two, pretty much every modern processor is affected to some extent, leaving users vulnerable to exploits that could allow an attacker to siphon potentially sensitive information from what is supposed to be a protected memory space.
Companies have been rushing to issue patches to mitigate the threats, both on the hardware and software side. One of the downsides is that some of these patches come with a performance penalty. More annoying, however, is that some systems are getting bricked in the early going, possibly because the patches are being rushed out the door.