I used my arduino uno to burn a bootloader to my ender 3 pro to update the firmware, now I cannot even write a sketch to the arduino nor upload as I get the message: can't set com state for com3. The driver for com3 for arduino is labelled "RAMPS" which caused me issues and I had to install a different driver previously. (WIN10x64) Also, while plugged into USB Arduino ON led is on and L led is on steady. It's becoming extremely frustrating. Can someone explain how to get this out of bootloading? Also, can someone explain what each LED on this board means? I've looked all over and get no useful info, I search for arduino uno status leds explained and get absolutely nothing that even tells me what the L led means. I am running arduino 1.8.9. I am trying to figure out how to use the uno to communicate with a futaba fp-r127df to control an RC submarine I am building but I can't even get the thing to communicate. Someone please help?
Sounds like a driver problem rather than any actual concern for the UNO. Is it in fact a real UNO?
On Windows, I have seen the COM ports get in a funky state and requires you to restart your PC. Have you tried that?