Where does it show 3.3V while VOUT is off?
The LCD shows the actual measured voltage, the bottom line of the toolbar shows live measurement. The only place it should say 3.3V if there is no voltage is in the top line of the toolbar.
Also, if you start the supply with W and the voltage does not reach the intended target, the power supply should report an error and disable itself. If voltage drops too much (10%) in the latest firmware you will also get an alarm and an error.
In general it should not be possible to enable the power supply if it does not output a voltage. However, I did a huge update this weekend and there are bound to be errors. I will debug this further if you can provide some additional information.
bus_pirate5_rev10.zip (393.3 KB)
Here is a firmware with the z/Z command in SPI mode based on the old PSU driver.