In order to conserve the limited bandwidth available, ISO images are not downloadable from mirror.centos.org

http://mirrors.advancedhosters.com/centos/8.4.2105/isos/ppc64le/
http://mirror.cs.vt.edu/pub/CentOS/8.4.2105/isos/ppc64le/
http://mirror.ash.fastserv.com/centos/8.4.2105/isos/ppc64le/
http://mirror.vtti.vt.edu/centos/8.4.2105/isos/ppc64le/
http://repos-va.psychz.net/centos/8.4.2105/isos/ppc64le/
http://us.mirror.nsec.pt/centos/8.4.2105/isos/ppc64le/
http://mirror.centos.iad1.serverforge.org/8.4.2105/isos/ppc64le/
http://mirror.vcu.edu/pub/gnu_linux/centos/8.4.2105/isos/ppc64le/
http://mirror.cogentco.com/pub/linux/centos/8.4.2105/isos/ppc64le/

http://mirror.mi.incx.net/centos/8.4.2105/isos/ppc64le/
http://mirrors.maine.edu/CentOS/8.4.2105/isos/ppc64le/
http://mirrors.oit.uci.edu/centos/8.4.2105/isos/ppc64le/
http://mirrors.rcs.alaska.edu/centos/8.4.2105/isos/ppc64le/
http://mirror.den01.meanservers.net/centos/8.4.2105/isos/ppc64le/
http://mirror.facebook.net/centos/8.4.2105/isos/ppc64le/
http://repo1.sea.innoscale.net/centos/8.4.2105/isos/ppc64le/
http://centos.den.host-engine.com/8.4.2105/isos/ppc64le/
http://mirrors.ocf.berkeley.edu/centos/8.4.2105/isos/ppc64le/
http://mirror.math.princeton.edu/pub/centos/8.4.2105/isos/ppc64le/
http://repos-lax.psychz.net/centos/8.4.2105/isos/ppc64le/
http://mirror.compevo.com/centos/8.4.2105/isos/ppc64le/
http://centos.mirror.ndchost.com/8.4.2105/isos/ppc64le/
http://mirrors.gigenet.com/centos/8.4.2105/isos/ppc64le/
http://mirrors.greenmountainaccess.net/centos/8.4.2105/isos/ppc64le/
http://mirrors.vcea.wsu.edu/centos/8.4.2105/isos/ppc64le/
http://mirror.grid.uchicago.edu/pub/linux/centos/8.4.2105/isos/ppc64le/
http://centos.mirror.lstn.net/8.4.2105/isos/ppc64le/
http://centos-distro.cavecreek.net/centos/8.4.2105/isos/ppc64le/
http://ftp.usf.edu/pub/centos/8.4.2105/isos/ppc64le/
http://mirror.dal.nexril.net/centos/8.4.2105/isos/ppc64le/
+ others, see the full list of mirrors: https://www.centos.org/download/mirrors/

Mirrors verified Fri Jun 18 15:32:06 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