Servidor: Raspberry Pi 3
OS: Dietpi - versión 159
Versión Geckodriver: 0.22 para brazo
Versión de Firefox: 52.9.0
Python versión: 3.5
Selenium versión: 3.14.1

Gecko es ejecutable y se encuentra en / usr / local / bin /

from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.firefox.options import Options
import time



options = Options()
options.set_headless(headless=True)
driver = webdriver.Firefox(firefox_options=options)

print('Need your login credential')
username = input('What is your username?:\n')
password = input('What is your password?:\n')
...
...

Salida

root@RPi3:~# python3.5 ITE-bot.py 
Traceback (most recent call last):
  File "ITE-bot.py", line 12, in <module>
    driver = webdriver.Firefox(firefox_options=options)
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/firefox/webdriver.py", line 174, in __init__
    keep_alive=True)
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/remote/webdriver.py", line 157, in __init__
    self.start_session(capabilities, browser_profile)
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/remote/webdriver.py", line 252, in start_session
    response = self.execute(Command.NEW_SESSION, parameters)
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/remote/webdriver.py", line 321, in execute
    self.error_handler.check_response(response)
  File "/usr/local/lib/python3.5/dist-packages/selenium/webdriver/remote/errorhandler.py", line 242, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.WebDriverException: Message: invalid argument: can't kill an exited process

¿Alguna idea de lo que está mal? He intentado google sin suerte.