Based on kernel version 4.9. Page generated on 2016-12-21 14:34 EST.
1 2 efivarfs - a (U)EFI variable filesystem 3 4 The efivarfs filesystem was created to address the shortcomings of 5 using entries in sysfs to maintain EFI variables. The old sysfs EFI 6 variables code only supported variables of up to 1024 bytes. This 7 limitation existed in version 0.99 of the EFI specification, but was 8 removed before any full releases. Since variables can now be larger 9 than a single page, sysfs isn't the best interface for this. 10 11 Variables can be created, deleted and modified with the efivarfs 12 filesystem. 13 14 efivarfs is typically mounted like this, 15 16 mount -t efivarfs none /sys/firmware/efi/efivars 17 18 Due to the presence of numerous firmware bugs where removing non-standard 19 UEFI variables causes the system firmware to fail to POST, efivarfs 20 files that are not well-known standardized variables are created 21 as immutable files. This doesn't prevent removal - "chattr -i" will work - 22 but it does prevent this kind of failure from being accomplished 23 accidentally.