Thank you for your reply and sorry for delay, I was offline.
There are 5 versions of TomTom ONE model (1st, 2nd, 3rd edition, 125/130 and 140 model version).
TomTom One 1st and 2nd edition support SD memory card. TomTom 3rd edition, TomTom 125/130 and 140 model doesn't have it.
First 3 version have "reset button". TomTom 123/130 and 140 model version doesn't have it.
Let's find out what is the version of your TomTom ONE model.
Check for serial number on your device. Serial number can be found on the bottom of your device.
If your model is ONE 3rd edition please check for reset button (check the picture below). Unfold a paperclip and slide an end into the hole.
Press and hold it for 25 seconds. When done, press and hold Power button for exactly 25 seconds.
3rd edition reset button
If your model is 125/130 or 140 please let me know.