Update your 3D printer firmware without a bootloader!


Use a USBtinyISP as a programmer or re-purpose an Arduino board you might already have to upload anything even to mainboards that do not come with a bootloader installed.


Hey @Thomas Sanladerer - I really need your help!!! After getting the USBTinyISP, I’ve followed your steps with no BOOTLOADER and here now my Ender 3 doesn’t boot up and remains on the blue screen with nothing. It is now refusing to communicate. :frowning:


If you can’t get the USBtinyISP to work, try using an Arduino as ISP according to Arduino’s manual: https://www.arduino.cc/en/tutorial/arduinoISP


Sounds good. Thank you for the direction.