In what circumstances will a court grant a peremptory writ to vacate an order denying petitioner's application for certificate of probable cause on the grounds that he waived his appellate rights?

In sum, we conclude the trial court erred in denying petitioner's application for certificate of probable cause on the ground he had waived his appellate rights. However, as in Drake v. Superior Court (2009) 175 Cal.App.4th 1462, "[w]e will not attempt to determine whether the application may be procedurally barred for some other reason, much less whether the trial court must issue a certificate of probable cause on the merits. We therefore issue a peremptory writ limited to directing the trial court to vacate its [waiver]-based order and to consider petitioner's application for a certificate of probable cause on the merits or other procedural grounds." (Id. at p. 1467.)