In the early days of DIY 3D printing, the standard Arduino Uno did not have enough processing power or memory for complex 3D printing movements. Makers turned to the ATmega644P chip. To make these chips work with the Arduino IDE, users had to install a "Board Support Package" (BSP).
A copy of this specific preloader file is hosted on Google Drive: Download preloader_k62v1_64_bsp.bin Common Use Cases Dead Boot Repair preloaderk62v164bspbin link