Skipping startup

Not sure if this is the right place to ask this but here it goes. I have a pocket computer i was coding during my process i named it startup and aparently i put in a shut down feature because as soon as it starts it says goodbye and shuts down not to restart until i use the pocket computer again. My question is if there is any way to bypass the startup program?

Place the pocket computer into a disk drive, then use another computer to alter / remove the startup file.

Thank you.