The fix to nrmp flash not working is to immediately spam the command again, so it will fail or give a tftp request error, immediately enter the command again, I copy and paste. Have you tried using these commands: nmrpflash -i net10 -f XR300-V1.0.3.34_10.3.27.chk Replace the firmware name with whatever file you are using. But it will say timeout something and just immediately copy and paste the command again, be quick. Always works for me when I am switching between firmwares like tomato to dumaos etc. As always with firmware updating, have nothing connected to the router except powerbank obviously, and your computer connected to the router in lan port 1, not wan port. Then set yourself a static ip address as well as a dns even though the dns server isn't necessary and try again. This is another command you can try, as always, replace the chk with the name of your firmware: nmrpflash -v -i net10 -f XR300-V1.0.3.34_10.3.27.chk -t 10000 -T 10000 -A 192.168.1.1 -a 192.168.1.1 . If you changed your gateway address from 192.168.1.1 to another, then replace that as well. Edit: I didn't read that you have solved your issue but I will leave this up incase this can help anyone else!