OP definitely should not do anything that might give the impression that they are abandoning their duties or, worse yet, actively sabotaging the company. That would be a dream come true for the other person’s lawyers.
If the OP wants to keep his equity, he needs to continue fulfilling his duties and demonstrate that he is, in fact, still working for the company.
Please don’t follow petty HN comment section advice like this. Not only is it unprofessional, but it can quickly turn into self-sabotage. Play it clean and don’t give the other side ammo to use against you in court.
You can frame it that way if you want but it's just not true.
OP has been doing X for 11 months, for free (well, for equity). Right now - today - he owns that equity, regardless of what his partner is asking him to do. If he stops doing X what is his argument against his partner and the investor - who own 50-60% of shares - saying that he's abdicating his duties?
This isn't sabotage, it's a labor strike until an equitable agreement is found.