How to update Chrome OS firmware to improve security
By Andy Wolber
1. Check Chrome OS firmware version
2. Save settings and files
3. Create Chrome recovery media
4. Update with a Powerwash
Full article:
https://www.techrepublic.com/article/how-to-update-chrome-os-firmware-to-improve-security/
See-also:
https://support.google.com/chromebook/answer/183084
https://support.google.com/chromebook/answer/3296214
https://support.google.com/chrome/a/answer/1360642
https://support.google.com/chromebook/answer/1080595
Firmware Security 