Before pleading guilty to drug and money-laundering charges, Lawrence Stevens filed two pro se motions for substitution of counsel. The motions were denied, and the district court 1 subsequently sentenced Stevens to 188 months in prison. On appeal, Stevens is represented by different counsel, who moves to withdraw and argues in a brief filed under Anders v. California, 386 U.S. 738, 87 S.Ct. 1396, 18 L.Ed.2d 493 (1967), that it was error to deny the pro se motions.

We hold that by pleading guilty, Stevens waived his right to challenge the denial of his pre-plea motions for substitute counsel. See United States v. Foreman, 329 F.3d 1037, 1038-39 (9th Cir. 2003) (right to appeal pre-plea motion for substitution of counsel is waived by unconditional guilty plea unless plea itself is challenged); cf. Tollett v. Henderson, 411 U.S. 258, 267, 93 S.Ct. 1602, 36 L.Ed.2d 235 (1973) (guilty plea represents break in chain of events which has preceded it in criminal process; when criminal defendant has solemnly admitted in open court that he is guilty of offense with which he is charged, he may not subsequently raise independent claims relating to deprivation of constitutional rights that occurred before entry of guilty plea; he may only attack voluntary and intelligent character of guilty plea by showing that advice he received from counsel was not within established standards).

We have reviewed the record independently in accordance with Penson v. Ohio, 488 U.S. 75, 109 S.Ct. 346, 102 L.Ed.2d 300 (1988), and have found no nonfrivolous is *971 sues. Accordingly, we grant counsel’s motion to withdraw, and we affirm.