"Resync" Mirage Island with RTC

[Taku86]

On my Pokémon Sapphire cartridge (live battery), the two bytes generated for Mirage Island don’t seem to match the progression of the RTC. According to my save file, 8965 days should have passed, and based on this list, Mirage Island should show the value FD00. However, I’m seeing D98D instead.

In the past, I used this save file on an emulator, and I think that may have desynchronized the RTC-related data on the cartridge (cartridge's RTC is currently set to today's/thread date, by the way). In fact, I know for certain that I started this playthrough on September 9, 2023, and I shouldn't be seeing 8965 days.

Is it possible to resync the RTC values to reflect the actual passage of time and make it so that, as of today (the date of writing this post) exactly 680 days have passed (from September 9, 2023) and the correct Mirage Island value appears?

 

Edited July 20, 2025 by Taku86