Dear @CarlosSierralta,
When you said… “I have modified the Mt_prep_gamma” , how had you done it exactly?
As I have already replied yesterday in this thread: Snap2stamps package: a free tool to automate the SNAP-StaMPS Workflow , you only need to modify the s by an f on the lines there mentioned.
Let me know and you still have the problem after trying that, I will share with you my modified script.
Regarding matlab, it can be run via GUI or via command line if you run it with the -nodesktop option.
I hope that this helps!