Ubuntu How can i get my USB wifi dongle to work after a reboot?

You can activate the wlan by these commands instead of repluging:

sudo modprobe -r 8192eu sudo modprobe 8192eu 

You need change 8192eu to your own wlan name. If you don’t know the name, search on google with keyword ID 148f:2070(your usb wlan’s id which can be found by command lsusb).

Or you can just add the wlan name to /etc/modules:

sudo -i echo 8192eu >> /etc/modules exit 

Then the wlan will be activated automatically when system start.