Datasheet

trinketblink.hex

https://adafru.it/cF1

And uploading it with the command avrdude -c usbtiny -p attiny85 -U flash:w:trinketblink.hex

or, if that's giving errors, avrdude -c usbtiny -p attiny85 -D -U flash:w:trinketblink.hex (note the extra -D)

As before, type out the command, then press the reset button to start the bootloader and once the red LED is pulsing,

hit return

When uploading, you will see a lot of avrdude: 8 retries during SPI command and similar warnings. THIS IS OK!

Because of the way the ATtiny85 works, there's a small delay when writing the new program to flash, and during that

delay, it cannot save the data and also send USB data at the same time. This causes the USB reply to avrdude to be

delayed and avrdude to spit out the retry alert.