How to burn an Arduino UNO bootloader to a new ATMEGA328P-AU chip
https://www.electronics-lab.com/how-to-burn-an-arduino-uno-bootloader-to-a-new-atmega328p-au-chip/
This video shows the steps to burn the bootloader from an Arduino UNO, to a new ATMEGA328P-AU chip. The new chips are the TQFP 32 type package. How to burn an Arduino UNO bootloader to a new ATMEGA328P-AU chip – [Link]