"The recent Linux kernel commits avoid one mechanism by which Samsung laptops can be bricked, but the information we now have indicates that there are other ways of triggering this," Garrett wrote in a separate post last Thursday. "We're still trying to figure out the full details, but until then you're safest ensuring that you're using BIOS mode on Samsung laptops no matter which operating system you're running."
Samsung laptops including the 530U3C, NP700Z7C, NP700Z5C, and 300E5C series are among those believed to be affected.
At the heart of the problem is that some Samsung laptops will fail to boot if too much of their variable storage space is used, Garrett explained.
"We don't know what 'too much' is yet, but writing a bunch of variables from Windows is enough to trigger it," he noted.
'Do not use UEFI'
Garrett has posted some sample code that writes out 36 variables, each containing one KB of random data. After running it as an administrator under Windows, he rebooted the system and "it never came back," he wrote.
Garrett's current conclusion is that the problem is caused by a firmware bug similar to some observed--but quickly fixed--in the past in Intel's reference code.
For now, "the safest thing to do is not to use UEFI on any Samsung laptops," he advised. "Unfortunately, if you're using Windows, that'll require you to reinstall it from scratch."