Login SSH to your endian firewall and try efw-upgrade -h
show the help!
root@efw:~ # efw-upgrade -h
Usage:
/usr/local/bin/efw-upgrade
Use -s to force channels setup and upgrade.
Use -u to change the email address used to register.
Use -h show this help.
Yeah! it easy way for change email, typing efw-upgrade -u
and enter new email address.
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Easy!