I know this thread is for pokemon gold but i think this is useful:
Actually there is a clockreset method in the titlescreen of pokemon crystal ... but it is much harder to get there as it was in gold/silver, here is a short tutorial:
1. Boot up the game to the titlescreen
2. Push and hold Down+B+Select
3. Release Down+B but keep Select hold down
4. Press Left+Up (still holding Select down)
5. Release the Select button
Now the password reset dialog should pop up ...
But I think this is far too complicated for daily use.
So here is a patch that allows you to reset the clock everytime you load a savegame of pokemon crystal for any version (language/region does not matter)
Pokemon Crystal RTC Patch
This patch does not seem to work correctly on VBA, but who cares if it's working well on the everdrive? ^^