Why the FBI wants you to reboot your router #feedme
Apparently, it has more to do with finding out the true extent of the malware infection. Rebooting does not actually remove the malware, updating the firmware does.
About the reasons: https://www.washingtonpost.com/news/posteverything/wp/2018/06/06/why-the-fbi-wants-you-to-reboot-your-router-and-why-that-wont-be-enough-next-time/?utm_term=.17676c6fa3f9
This article has more thorough instructions and a list of vulnerable routers: https://www.komando.com/happening-now/464402/fbi-router-warning-infecting-500000-devices-is-worse-than-they-led-on
Enjoy your 20% upvote, @rufusfirefly!