[Map] Advance Map Help

Having an issue with Advance Map, pretty sure it's something small I'm doing incorrectly. Been updating a lot of the tiles in Emerald, however when I try and replace the rocks on route 111 with new ones I've inserted, I change the tiles in Advance Map and everything appears to be fine, however when I load up the game the tiles have not changed. Any knowledge on this issue would be appreciated .

Try saving the ROM.

Don't be silly mate.

Ended up getting the issue solved with some help, not saving the rom in advance map was not the issue.