firmware_variables

Python library for controlling UEFI variables in Windows.

Requirements

• Windows ≥ 8
• Python ≥ 3.7 (might work on Python >= 2.7 but not formally supported)
• UEFI Firmware (required for most APIs)
• Administrative privileges (required for most APIs)

Installation

pip install firmware_variables

Usage

Run as Administrator

Read variables

from firmware_variables import *

# Acquire privileges to read the firmware state in your process
with adjust_privileges():
    # Read the current boot id 
    data, attr = get_variable("BootCurrent")
    print(data)
    print(attr)

Output:

b'\x00\x00'
Attributes.RUNTIME_ACCESS|BOOT_SERVICE_ACCESS

Display the boot order

from firmware_variables import *

with adjust_privileges():
    for entry_id in get_boot_order():
        load_option = get_parsed_boot_entry(entry_id)
        print(f"{entry_id} {load_option}")

Output:

0 <Windows Boot Manager \EFI\MICROSOFT\BOOT\BOOTMGFW.EFI [LoadOptionAttributes.LOAD_OPTION_ACTIVE]>
2 <Hard Drive <Custom Location> [LoadOptionAttributes.LOAD_OPTION_ACTIVE]>

Manipulate system state

Caution: The following commands will modify your system state.
Do not run it on your host machine unless you know what you're doing.

from firmware_variables import *

with adjust_privileges():

    # Create a new variable
    set_variable("Test", b"\x00",
    namespace="{f29e2c32-8cca-44ff-93d7-87195ace38b9}", 
    attributes= Attributes.NON_VOLATILE | 
                Attributes.BOOT_SERVICE_ACCESS |
                Attributes.RUNTIME_ACCESS)
    
    # Delete it
    delete_variable("Test", namespace="{f29e2c32-8cca-44ff-93d7-87195ace38b9}")
    
    # Add a new entry id to your boot order
    order = get_boot_order()
    new_id = max(order) + 1
    set_boot_order(order + [new_id])
    
    # Read the first boot entry
    load_option = get_parsed_boot_entry(order[0])
    load_option.description = "My Boot Entry"
    load_option.file_path_list.set_file_path(r"\EFI\Boot\myfile.efi")
    
    # Create our new boot entry based on the first entry
    set_parsed_boot_entry(new_id, load_option)