(c) Challenges to the validity of a certificate of compliance or supplemental certificates of compliance served on the defense and filed with the court pursuant to subdivision one of this section shall be addressed by motion within thirty-five days of the service of the certificate provided that the prosecution has filed an indictment or information prior to filing the certificate of compliance. Nothing in this section shall be construed to waive a party's right to file a motion pursuant to section 30.30 of this chapter on grounds unrelated to the validity of a certificate of compliance. Provided, however, that any challenges to a certificate of compliance or supplemental certificate of compliance shall be accompanied by an affirmation by the moving party that, after the filing of the opposing party's certificate of compliance, such moving party timely conferred in good faith or timely made good faith efforts to confer with the opposing party regarding the specific and particularized matters forming the basis for such challenge, that efforts to obtain the missing discovery from the opposing party or otherwise resolve the issues raised were unsuccessful, and that no accommodation could be reached. For the purposes of this subdivision, the parties may confer informally, including but not limited to communication by email, telephone, or any other reasonable means.

1. (i) Upon request, the court may extend the time period to challenge a certificate of compliance or supplemental certificate of compliance beyond the thirty-five days for good cause shown. A request for extension shall be made before the expiration of the thirty-five days. Unless the court finds that the prosecutor unreasonably delayed in responding to the defense's good faith efforts to confer or that the prosecutor did not file the certificate of compliance in good faith, any such extension shall be excluded from a speedy trial calculation pursuant to paragraph (b) of subdivision four of section 30.30 of this chapter.
2. (ii) Notwithstanding the provisions of this subdivision, a party may challenge the validity of the certificate of compliance after the expiration of the thirty-five day period where the grounds for such challenge are based upon a material change in circumstances, including but not limited to the belated disclosure of discoverable material pursuant to section 245.20 of this article, or, where the party entitled to disclosure could not, with due diligence, have known of the specific and particularized matters forming the basis of the challenge prior to the expiration of such period.
3. (iii) Nothing in this subdivision shall limit the court's authority to facilitate compliance pursuant to section 245.35 of this article. Any extension of time granted pursuant to section 245.35 shall be excluded from a speedy trial calculation pursuant to paragraph (b) of subdivision four of section 30.30 of this chapter.

4. 5. Assessing due diligence. In assessing a party's due diligence, the court shall look at the totality of the party's efforts to comply with the provisions of this article, rather than assess the party's efforts item by item.

   1. (a) Relevant factors for assessing the prosecutor's due diligence include, but are not limited to: the efforts made by the prosecutor to comply with the requirements of this article; the volume of discovery provided and the volume of discovery outstanding; the complexity of the case; whether the prosecutor knew that the belatedly disclosed or allegedly missing material existed; the explanation for any alleged discovery lapse; the prosecutor's response when apprised of any allegedly missing discovery; whether the belated discovery was substantively duplicative, insignificant, or easily remedied; whether the omission was corrected; whether the prosecution self-reported the error and took prompt remedial action without court intervention; and whether the prosecution's delayed disclosure of discovery was prejudicial to the defense or otherwise impeded the defense's ability to effectively investigate the case or prepare for trial.
   2. (b) The court's determination shall be based on consideration of all factors listed in paragraph (a) of this subdivision and no one factor shall be determinative. The court shall explain the basis for its determination on the record or in writing.
   3. (c) A finding of a valid certificate under this section shall constitute a valid certificate pursuant to subdivision five of section 30.30 of this chapter. Upon a finding of a valid certificate, the court shall, if warranted, fashion an appropriate and proportional remedy for any discovery violation resulting from the belated disclosure pursuant to subdivision two of section 245.80 of this article.
5. 6. Determinations by the court. Notwithstanding any other section of law to the contrary, a court shall not invalidate a certificate of compliance where the party has exercised due diligence and acted in good faith in making reasonable inquiries and efforts to obtain and provide the material required to be disclosed pursuant to section 245.20 of this article.