The cool thing about the bootloader on the Pro Trinket is it just looks like a classic USBtinyISP AVR programmer. This makes it easy to use with AVRdude or Arduino IDE with only minor configuration changes. Before you start, you may need to install the USBtinyISP USB drivers | The cool thing about the bootloader on the Pro Trinket is it just looks like a classic USBtinyISP AVR programmer. This makes it easy to use with AVRdude or Arduino IDE with only minor configuration changes. Before you start, you may need to install the USBtinyISP USB drivers |