Review: SparkFun Pro Micro RP2040 - Make: DIY Projects and Ideas for Makers
ATmega32U4 Mega32U4 5V 16MHz Module Pro Micro USB Controller Board for Arduino Nano Mini Leonardo ATMEGA32U4-AU with Bootloader: Amazon.com: Industrial & Scientific
Reinstall bootloader for an Arduino Pro Micro?
Arduino MICRO Bootloader Burn
Pro Micro & Fio V3 Hookup Guide - SparkFun Learn
Pro Micro & Fio V3 Hookup Guide - SparkFun Learn
Flash your Pro Micro with Hex file without Arduino
Tom's computer pages
How to Upload Sketches to Pro Micro/Leonardo Via Serial Bluetooth : 12 Steps - Instructables
Arduino fix bootloaded
Pro Micro & Fio V3 Hookup Guide - SparkFun Learn
Pro Micro & Fio V3 Hookup Guide - SparkFun Learn
SOLVED] Problem to upload to Pro Micro - Microcontrollers - Arduino Forum