MEMORANDUM **
Michael Craig Dickman appeals his guilty plea conviction and 108-month sentence imposed for six counts of bank robbery, in violation of 18 U.S.C. § 2113(a). We have jurisdiction pursuant to 28 U.S.C. § 1291, and we affirm.
Dickman contends the district court erred in dismissing his pretrial motions to suppress evidence. Because Dickman entered a valid unconditional guilty plea, he waived the right to raise the denial of his *439motion to suppress on appeal. See United States v. Floyd, 108 F.3d 202, 204 (9th Cir.1997) (holding that an unconditional guilty plea constitutes a waiver of the right to appeal all non-jurisdictional antecedent rulings and cures all antecedent constitutional defects).
Second, Dickman contends the district court erred by declining to grant downward departure for aberrant behavior. A district court’s discretionary refusal to depart from a prescribed sentencing guideline range is unreviewable on appeal unless the district court rested its decision on an erroneous belief that it lacked the authority to do so. United States v. Morales, 898 F.2d 99, 101-02 (9th Cir.1990). Because the district court properly exercised its discretion, we lack jurisdiction to review this issue. Id.
Third, Dickman contends that the district court violated his due process rights by granting an obstruction of justice upward adjustment based on unreliable hearsay statements. Because the government’s offer of proof provided more than minimal indicia of reliability in corroborating the use of hearsay testimony, no due process violation occurred. United States v. Petty, 982 F.2d 1365 1369 (9th Cir.1993).
AFFIRMED.
This disposition is not appropriate for publication and may not be cited to or by the courts of this circuit except as may be provided by Ninth Circuit Rule 36-3.