Samsung UEFI bug definitely not fixed

The Samsung 900X4C is one of the affected devices. As well as the samsung-laptop Linux driver, there are other ways of confusing the firmware on some Samsung laptops in UEFI mode to the extent that they will no longer boot. Matthew Garrett indicated as much in a recent blog post, in which he says that it appears that even normal userspace applications in Windows are able to trigger the problem. The kernel developer advises users to run in BIOS mode whatever their operating system. This requires instructing the UEFI firmware to use the CSM (compatibility support module) to boot the operating system; operating systems installed in UEFI mode are, however, unable to boot via CSM.

Garrett, who was involved in work on UEFI support in the Linux kernel, bases his comments on the information available to him. His comment about other ways of triggering the problem chimes with a report from a reader who, in creating UEFI boot entries, managed to confuse the firmware on his Samsung laptop to the extent that it was no longer possible to access the UEFI setup. When the problem first came to light, Greg Kroah-Hartman, who worked on the samsung-laptop driver, made it clear in a post on Google+ that, in his view, Samsung was the only party in a position to resolve the cause of the problem and that a firmware update was required.

According to current understanding, the problem affects at least 300E5C, 530U3C, 700Z3C, 700Z5C, 700Z7C and 900X4C series Samsung laptops. Changes have now been merged into Linux versions 3.8-rc6, 3.7.6 and 3.2.38, which deactivate the samsung-laptop driver when booting via UEFI to prevent damage to the laptop.

A firmware update to fix the problem is not yet in sight.
According to the Ubuntu bug report which first brought the problem to light, Samsung developers were aware of the problem several weeks ago. A comment by Canonical and Debian developer Steve Langasek, posted several days ago, revealed that the Samsung development team had recently made major progress in their investigations, but it remains unclear when a firmware update will be released.

(djwm)