Often requires two separate computers if using both v1.20 and v1.21 clones, or they will conflict. Recommendation
Connect your J2534 device (e.g., Scanmatik 2 Pro) to the laptop and the vehicle’s OBD-II port or directly to the ECU pins for "Bench" mode operations. pcmflash 120 download link
If you're interested in downloading PCMFlash 120, here are some steps to follow: Often requires two separate computers if using both v1
Install the Guardant drivers before plugging in the USB dongle. pcmflash 120 download link
Very inexpensive compared to original; includes many active modules. Cons: Known to have issues with newer vehicle protocols.