I recently tried to install a bootloader on my Creality Ender 3 1.1.4 board. I followed an all in one raspberry pi method and after flashing plugged it into my PC to update the firmware.
However, the system couldn't find any device drivers to talk to the printer - it just kept showing up as a USB2.0-serial device
Thankfully someone on reddit (https://www.reddit.com/r/3Dprinting/comments/93zah2/so_i_just_bricked_by_ender_3_through_a_firmware/ TrueShoba) had a link to the below package, which once installed allowed me to flash the new firmware to the system
thank goodness! I now have a Marlin 2.0 Ender 3 to play with :)