Does a defendant have to plead guilty to a charge of assault with intent to commit a firearm enhancement if he failed to secure a certificate of probable cause?

People v. Lobaugh (1987) 188 Cal.App.3d 780 is likewise instructive. In that case, the defendant pleaded guilty to robbery and admitted a firearm use enhancement, a prior serious felony conviction, and a prior prison term allegation. (Id. at p. 783.) On appeal, the defendant sought to challenge the sufficiency of the evidence to support the firearm use enhancement. (Id. at p. 785.) Although the defendant had failed to secure a certificate of probable cause, the appellate court concluded the issue would not have been cognizable on appeal even if the trial court had granted a certificate of probable cause, reasoning that "any error relating to the sufficiency of the evidence does not go to the legality of the proceeding, was waived by his guilty plea and may not be raised on appeal." (Ibid.)