                  placing him on the law library list was inadequate. Appellant failed to
                  demonstrate an impediment external to the defense to excuse his
                  procedural defect. See Hathaway v. State, 119 Nev. 248, 252, 71 P.3d 503,
                  506 (2003). His lack of legal assistance did not constitute good cause to
                  excuse the delay. See Phelps v. Dir., Nev. Dep't of Prisons, 104 Nev. 656,
                  660, 764 P.2d 1303, 1306 (1988). He also did not demonstrate that a
                  three-week deprivation of access to a law library prevented him from filing
                  a timely petition when he had an entire year to file it, nor did he provide
                  specific facts to demonstrate that the prison's law library system
                  interfered with his ability to file a timely petition. See Hargrove a State,
                  100 Nev. 498, 502,686 P.2d 222, 225 (1984).
                                Appellant also asserted that the procedural bar did not apply
                  to him because he was challenging the jurisdiction of the district court to
                  impose a habitual criminal enhancement and jurisdictional claims may be
                  raised at any time. Appellant's assertion was without merit, as
                  appellant's claims challenged the validity of the judgment of conviction
                  and sentence and did not implicate jurisdiction. See NRS 34.720(1); NRS
                  34.724(1); see also Nev. Const. art. 6, § 6; NRS 171.010. Therefore, we
                  conclude that the district court did not err in denying his post-conviction
                  petition for a writ of habeas corpus as procedurally barred. Accordingly,
                  we
                                ORDER the judgment of the district court AFFIRMED.



                                                                         J.
                                           Picker:1i:


                                                  J.                                       J.
                  Parraguirre                                Saitta
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                cc: Hon. Douglas W. Herndon, District Judge
                     Andrew Jefferson
                     Attorney General/Carson City
                     Clark County District Attorney
                     Eighth District Court Clerk




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