Raymond Alphonso Daley, a federal prisoner (# 89980-079), moves for a certificate of appealability (“COA”) to appeal the *643 district court’s denial of his 28 U.S.C. § 2255 motion to vacate his sentence. Following a remand by this court pursuant to Thompson v. Montgomery, 853 F.2d 287 (5th Cir. 1988), the district court determined that Daley had failed to establish that he had filed a timely notice of appeal. The clerk’s office has directed Daley to brief this jurisdictional issue, but he has faded to do so. Daley has effectively abandoned any challenge to the district court’s determination that his notice of appeal was untimely, see Brinkmann v. Dallas County Deputy Sheriff Abner, 813 F.2d 744, 748 (5th Cir. 1987), and this court is without appellate jurisdiction. See Dison v. Whitley, 20 F.3d 185, 186 (5th Cir. 1994). Accordingly, the appeal is DISMISSED. Daley’s COA application is DENIED as moot.

APPEAL DISMISSED; COA DENIED AS MOOT.