Lots of garbage on serial with 8 MHz standalone internal oscillator

If any part of burning the bootloader succeeded when Uno was the selected board then any further attempts at serial programming will require an external clock (crystal+caps, resonator, or clock signal on XTAL1). I have no idea if high-voltage parallel programming will require an external clock. I suggest getting an external clock connected before continuing. If nothing else doing that will eliminate it as the problem.

I have a variation of the ArduinoISP sketch that provides a suitable clock signal. If you'd like a copy send me a Personal Message.