Some of the tinyAVR devices has a TPI interface, which supports external programming of all non-volatile memories.
The TPI interface requires two of the device's pins, TPIDATA and TPICLK, in addition to the RESET pin. On QT600, they are found on the ISP/PDI connector.
If the device has a Reset Disable fuse, and this fuse is programmet, it is not possible to connect to the device using QT600. You will then need an STK600 to be able connect to it again. QT600 can not generate a 12V signal on the RESET line which is required to enter programming mode.