Firmware Not Uploading To Printer

I am at my wits end…I am trying to upload firmware to adjust the height of the print head properly on my Keyes Rostok printer and it’s not working. I keep getting the same blasted error and it’s really upsetting me. I use a 3D printer for my costuming business and people are starting to ask where their order are :frowning: Please, someone help :frowning:


I agree with @spycatcher2k. This Forum is for helping people write their own Arduino programs, not for sorting out problems on commercial products.