This security setting determines who can modify firmware environment values. Firmware environment variables are settings stored in the nonvolatile RAM of non-x86-based computers. The effect of the setting depends on the processor.

On x86-based computers, the only firmware environment value that can be modified by assigning this user right is the Last Known Good Configuration setting, which should only be modified by the system.
On Itanium-based computers, boot information is stored in nonvolatile RAM. Users must be assigned this user right to run bootcfg.exe and to change the Default Operating System setting on Startup and Recovery in System Properties.
On all computers, this user right is required to install or upgrade Windows.

Note: This security setting does not affect who can modify the system environment variables and user environment variables that are displayed on the Advanced tab of System Properties. For information about how to modify these variables, see To add or change the values of environment variables.