In order to reset zim network parameters, zim needs to be switched on for at least two minutes.
With a paper clip (or print the attached reset button), press on the button inside zim (as indicated on the picture below) until you hear or feel the little click of the button.
Wait for about 10 seconds then Switch off the printer then switch it on again.
You should see "zim_initalizationxxx" appear in the list of available wifi networks form a wifi enabled device (PC/Mac/tablet/smartphone)
(xxxx represents the four last digits of zim serial number which may be found on a sticker beneath zim)