Mass. Gen. Laws ch. 278A, § 15: Waiver of right to file motion prohibited

Section 15. The right to file a motion under this chapter shall not be waived. This prohibition of any waiver includes, but is not limited to, any stated or unstated waiver that is or is alleged to be part of any agreement or understanding related to any plea of guilty or of nolo contendere or to any sentencing or appellate proceeding or to any correctional placement or conditions.