Is there any evidence that counsel was ineffective on appeal?

There is nothing in the record on appeal suggesting that counsel was ineffective. If matters occurred off record, defendant's relief is by way of habeas corpus. Finally, counsel suggests we consider whether defendant's plea was "knowing, intelligent, and otherwise valid." But defendant may not challenge the validity of his plea unless he first obtains a certificate of probable cause to appeal. (Pen. Code, 1237.5; People v. Mendez (1999) 19 Cal.4th 1084, 1095.) Defendant applied for the certificate, but it was denied. Thus, we may not consider the validity of his plea.