Both the substantive and procedural provisions of this chapter shall apply to any action for post-conviction review commenced after the effective date of this chapter. In the case of any action under former Title 14, sections 5502 to 5508 or any other action for collateral review of a conviction or of consequences resulting from a criminal judgment which was commenced prior to the effective date of this chapter and which is pending on the effective date, the petition may be amended to assert any basis for jurisdiction under section 2124 or any grounds for relief not available under prior law; provided that failure to do so shall not constitute waiver pursuant to section 2128, subsection 3. In any pending action brought under prior law, the court in its discretion may apply any of the procedural provisions of this chapter. [PL 1987, c. 402, Pt. A, §111 (AMD).]