If it had a bootloader you could use Tx and Rx along with an FTDI cable. Or you could wire up the ISCP interface to the SPI pins. Or both, in case you needed to use ICSP to put the bootloader there in the first place.
If it had a bootloader you could use Tx and Rx along with an FTDI cable. Or you could wire up the ISCP interface to the SPI pins. Or both, in case you needed to use ICSP to put the bootloader there in the first place.