Changing or Setting TIMEZONE in kerlink ifemtocell gateway

Hi guys
I have a kerlink ifemtocell configured with NTP client, and have timezone set to GMT+0 and need to set to GMT-3.

I have tried to do with this command

cp /usr/share/zoneinfo/Etc/GMT-3 /etc/localtime

cp: can’t create ‘/etc/localtime’: File exists

And receive the “File exists” error.

ln -s /usr/share/z oneinfo/Etc/GMT-3 /etc/localtime

ln: /etc/localtime: File exists

does not work.

unlink /etc/localtime

unlink: can’t remove file ‘/etc/localtime’: Read-only file system

does not work…

Due this missconfiguration, all logs and with time differences.

Any help on this issue will be welcomed.

THanks

Hugo