efivarfs - a (U)EFI variable filesystemThe efivarfs filesystem was created to address the shortcomings ofusing entries in sysfs to maintain EFI variables. The old sysfs EFIvariables code only supported variables of up to 1024 bytes. Thislimitation existed in version 0.99 of the EFI specification, but wasremoved before any full releases. Since variables can now be largerthan a single page, sysfs isn't the best interface for this.Variables can be created, deleted and modified with the efivarfsfilesystem.efivarfs is typically mounted like this, mount -t efivarfs none /sys/firmware/efi/efivars
Due to the presence of numerous firmware bugs where removing non-standardUEFI variables causes the system firmware to fail to POST, efivarfsfiles that are not well-known standardized variables are createdas immutable files. This doesn't prevent removal - "chattr -i" will work -but it does prevent this kind of failure from being accomplishedaccidentally.