A defendant may challenge the legality of his sentence, including a challenge on Penal Code section 654 grounds, without obtaining a certificate of probable cause if the plea agreement did not specify a maximum sentence. Here, the defendant entered into a plea agreement, and although the parties did not agree to a maximum sentence, the judge advised the defendant at the time of the plea of the maximum sentence he could receive under the terms of the agreement. On remand from the Supreme Court after People v. Shelton (2006) 37 Cal.4th 759, the appellate court found that Shelton did not apply because the parties did not bargain for a maximum term. The court also rejected the People’s argument that the defendant’s 654 challenge was barred by Rule 4.412(b), because the parties had not agreed to a specified sentence.