In order to conserve the limited bandwidth available, ISO images are not downloadable from mirror.centos.org
The following mirrors should have the ISO images available:
http://mirror.cs.vt.edu/pub/CentOS/8.4.2105/isos/aarch64/
http://atl.mirrors.clouvider.net/CentOS/8.4.2105/isos/aarch64/
http://distro.ibiblio.org/centos/8.4.2105/isos/aarch64/
http://nyc.mirrors.clouvider.net/CentOS/8.4.2105/isos/aarch64/
http://mirrors.rcs.alaska.edu/centos/8.4.2105/isos/aarch64/
http://linux.cc.lehigh.edu/centos/8.4.2105/isos/aarch64/
http://mirror.umd.edu/centos/8.4.2105/isos/aarch64/
http://repos.dfw.quadranet.com/centos/8.4.2105/isos/aarch64/
http://us.mirror.nsec.pt/centos/8.4.2105/isos/aarch64/
http://mirror.hackingand.coffee/centos/8.4.2105/isos/aarch64/
http://mirror.centos.iad1.serverforge.org/8.4.2105/isos/aarch64/
http://mirror.us-midwest-1.nexcess.net/CentOS/8.4.2105/isos/aarch64/
http://ftp.ussg.iu.edu/linux/centos/8.4.2105/isos/aarch64/
http://mirrors.cat.pdx.edu/centos/8.4.2105/isos/aarch64/
http://mirror.netdepot.com/centos/8.4.2105/isos/aarch64/
http://packages.oit.ncsu.edu/centos/8.4.2105/isos/aarch64/
http://repo1.dal.innoscale.net/centos/8.4.2105/isos/aarch64/
http://sjc.edge.kernel.org/centos/8.4.2105/isos/aarch64/
http://mirrors.rit.edu/centos/8.4.2105/isos/aarch64/
http://mirror.cogentco.com/pub/linux/centos/8.4.2105/isos/aarch64/
http://mirror.arizona.edu/centos/8.4.2105/isos/aarch64/
http://mirror.rackspace.com/CentOS/8.4.2105/isos/aarch64/
http://mirror.facebook.net/centos/8.4.2105/isos/aarch64/
http://repo1.sea.innoscale.net/centos/8.4.2105/isos/aarch64/
http://mirrors.gigenet.com/centos/8.4.2105/isos/aarch64/
http://ewr.edge.kernel.org/centos/8.4.2105/isos/aarch64/
http://mirror.mi.incx.net/centos/8.4.2105/isos/aarch64/
http://centos.den.host-engine.com/8.4.2105/isos/aarch64/
http://repos-lax.psychz.net/centos/8.4.2105/isos/aarch64/
http://mirror.atl.genesisadaptive.com/centos/8.4.2105/isos/aarch64/
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/
Mirrors verified Mon Nov 15 16:37:12 2021 UTC
You can also download the ISO images using bittorrent, a peer-to-peer file sharing protocol. The .torrent files can be found from CentOS mirrors. Various bittorrent clients are available, including (in no particular order of preference): utorrent, vuze (Azureus), BitTorrent, Deluge, ctorrent, ktorrent, rtorrent and transmission. Packaged copies of various torrent clients for CentOS can be found in the repositories listed in the following wiki article: https://wiki.centos.org/AdditionalResources/Repositories
The following mirrors should have the ISO images available:
http://mirror.cs.vt.edu/pub/CentOS/8.4.2105/isos/aarch64/
http://atl.mirrors.clouvider.net/CentOS/8.4.2105/isos/aarch64/
http://distro.ibiblio.org/centos/8.4.2105/isos/aarch64/
http://nyc.mirrors.clouvider.net/CentOS/8.4.2105/isos/aarch64/
http://mirrors.rcs.alaska.edu/centos/8.4.2105/isos/aarch64/
http://linux.cc.lehigh.edu/centos/8.4.2105/isos/aarch64/
http://mirror.umd.edu/centos/8.4.2105/isos/aarch64/
http://repos.dfw.quadranet.com/centos/8.4.2105/isos/aarch64/
http://us.mirror.nsec.pt/centos/8.4.2105/isos/aarch64/
http://mirror.hackingand.coffee/centos/8.4.2105/isos/aarch64/
http://mirror.centos.iad1.serverforge.org/8.4.2105/isos/aarch64/
http://mirror.us-midwest-1.nexcess.net/CentOS/8.4.2105/isos/aarch64/
http://ftp.ussg.iu.edu/linux/centos/8.4.2105/isos/aarch64/
http://mirrors.cat.pdx.edu/centos/8.4.2105/isos/aarch64/
http://mirror.netdepot.com/centos/8.4.2105/isos/aarch64/
http://packages.oit.ncsu.edu/centos/8.4.2105/isos/aarch64/
http://repo1.dal.innoscale.net/centos/8.4.2105/isos/aarch64/
http://sjc.edge.kernel.org/centos/8.4.2105/isos/aarch64/
http://mirrors.rit.edu/centos/8.4.2105/isos/aarch64/
http://mirror.cogentco.com/pub/linux/centos/8.4.2105/isos/aarch64/
http://mirror.arizona.edu/centos/8.4.2105/isos/aarch64/
http://mirror.rackspace.com/CentOS/8.4.2105/isos/aarch64/
http://mirror.facebook.net/centos/8.4.2105/isos/aarch64/
http://repo1.sea.innoscale.net/centos/8.4.2105/isos/aarch64/
http://mirrors.gigenet.com/centos/8.4.2105/isos/aarch64/
http://ewr.edge.kernel.org/centos/8.4.2105/isos/aarch64/
http://mirror.mi.incx.net/centos/8.4.2105/isos/aarch64/
http://centos.den.host-engine.com/8.4.2105/isos/aarch64/
http://repos-lax.psychz.net/centos/8.4.2105/isos/aarch64/
http://mirror.atl.genesisadaptive.com/centos/8.4.2105/isos/aarch64/
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/
Mirrors verified Mon Nov 15 16:37:12 2021 UTC
You can also download the ISO images using bittorrent, a peer-to-peer file sharing protocol. The .torrent files can be found from CentOS mirrors. Various bittorrent clients are available, including (in no particular order of preference): utorrent, vuze (Azureus), BitTorrent, Deluge, ctorrent, ktorrent, rtorrent and transmission. Packaged copies of various torrent clients for CentOS can be found in the repositories listed in the following wiki article: https://wiki.centos.org/AdditionalResources/Repositories