Copy AT&T certificates from your AT&T Gateway. See the below for assistance:

https://www.reddit.com/r/ATT/comments/g59rwm/bgw210700_root_exploitbypass/

https://github.com/bypassrg/att

For Asus routers asus-merlin.net

For Linksys routers Linksys EA6400 (Koolshare port)

Main Page, Administration, System "Enable JFFS custom scripts and configs." Uncheck "Format JFFS".

Also enable "SSH Server Daemon" just below this (see screenshot).

Putty will be used to ssh to the Asus-Merlin router. Pscp will be used to transfer files to/from the Asus-Merlin router. Both are included in the Putty installation.

Putty

edit wpa_supplicant.conf

ca_cert="/jffs/802.1x/CA_XXXXXX.pem"

client_cert="/jffs/802.1x/Client_XXXXXX.pem"

private_key="/jffs/802.1x/PrivateKey_PKCS1_XXXXXX.pem"

ssh to Asus-Merlin router (use Putty)

cd /jffs; mkdir 802.1x

from your Windows PC:

(change to directory where your AT&T certificates and the below scripts have been downloaded to)

"C:\Program Files\PuTTY\pscp" -scp *.pem admin@asus.router.com:/jffs/802.1x/

"C:\Program Files\PuTTY\pscp" -scp wpa_supplicant.conf admin@asus.router.com:/jffs/802.1x/

"C:\Program Files\PuTTY\pscp" -scp services-start admin@asus.router.com:/jffs/scripts/

"C:\Program Files\PuTTY\pscp" -scp windate admin@asus.router.com:/jffs/

"C:\Program Files\PuTTY\pscp" -scp xfinitywifi admin@asus.router.com:/jffs/

chmod +x /jffs/scripts/services-start

chmod +x /jffs/windate

chmod +x /jffs/xfinitywifi

During startup, the Asus-Merlin gateway will attempt to connect to "xfinitywifi," an open network hotspot in order to synchronize the date and time. If this network is not available to you, you will need to install your own time/NTP server on your home network. I have simple instructions on how to do that as well in the next step.