time date change

Hi after flashing my box a few weeks ago the time is out by about 20 min when i change this through telnet it goes back to the worng time again soon after must be updating from sat feed is there a way to fix this.

Thanks

Hi stevejo I only get an option to select timezone not the time it's set at Greenwich mean time Dublin Lisbon London i can't find a option in menu to set the time itself could you let me know we're i can find it Thanks