I debugged my v1 before when you do you put very light pencil marks, I then undebugged it because I hated it.
I debugged it right so the undebugging worked.
To undebugg your tama go back to the memory chip.
You know the little circle you lightly coloured with a pencil while debugging?
Take a very small eraser and lightly erase it back and forth a couple times so your pencil markings are gone.
Put the back on and the battry in if it didn't work open it back up and erase more.
Close it and put the battry in reset it again, it should have worked, if not your tamagotchi is screwed forever.
Debugging is a major DANGER and only debugg if you are willing to sacrifce breaking your tamagotchi.
Take MY advice I have debugged and undebugged over 5 tamagotchis.