your success with this really depends on router manufacturer and hardware used
i have successfully managed to reboot tg782i router but only when connected to it's wifi
if you are interested in exploring this the process involves running a couple of concurent nmap scans. i usually open 4-5 terminal windows and run nmap -v -A xxx.xxx.xxx.xxx
once the basic scans are done and nmap script engine launches scripts against a router it freezes and restarts. sometimes it's neccessary to repeat the process a few times but if you could narrow down the script that does this it might be useful to try to forge a packet that could be sent in monitor mode.
the mentioned router uses crappy broadcom chipset and it's very likely other thomson/technicolor models are vulenerable to this bug