Pokemon Emerald Real Time Clock Patch
There’s an unreleased Mystery Event that causes the message “The in-game clock adjustment function is now useable.” to be displayed. After it’s activated, pressing Left + Select + B on the title screen will open a screen which asks “Reset RTC?” and then invites you to “Please reset the time” with options to adjust the day number, hours, minutes, and seconds. For obvious reasons, it was never actually released in the form of an e-Reader card, but one could be made. From my limited experimentation, I think it only adjusts the save file timestamp rather than the RTC itself. There’s an unreleased Mystery Event that causes the message “The in-game clock adjustment function is now useable.” to be displayed.
For Pokemon Emerald Version on the Game Boy Advance, a GameFAQs Answers question titled 'Why does the game keep telling me that the game has been erased due to corruption or damage when the credits end?' Go to Options > Emulator > Real Time Clock, this resolves the time based events problem. Now go to Options > Emulator > Save Type > Flash.
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After it’s activated, pressing Left + Select + B on the title screen will open a screen which asks “Reset RTC?” and then invites you to “Please reset the time” with options to adjust the day number, hours, minutes, and seconds. For obvious reasons, it was never actually released in the form of an e-Reader card, but one could be made. Technosat.
From my limited experimentation, I think it only adjusts the save file timestamp rather than the RTC itself. They have two v1.1 “bad dumps” listed under the entries for Japanese v1.0.
I just looked into those and am fairly certain that the “PROPER GBA-COS” releases (MD5 Ruby 20449ADAB693BF966BF0F4A907102FB9 and Sapphire ABF042BE32E2AEAB1B926EFE6D4B8B8B) are accurate dumps. Only four bytes are changed between Japanese v1.0 and v1.1: two bytes in the cartridge header to update the version number and two bytes in the ymdToDateNumber function to fix the Berry glitch. The difference between the verified dumps of English v1.1 and v1.2 is these same four bytes. (I wish I’d known that earlier; it would’ve made it easy to spot the bug ). There’s an unreleased Mystery Event that causes the message “The in-game clock adjustment function is now useable.” to be displayed.
After it’s activated, pressing Left + Select + B on the title screen will open a screen which asks “Reset RTC?” and then invites you to “Please reset the time” with options to adjust the day number, hours, minutes, and seconds. For obvious reasons, it was never actually released in the form of an e-Reader card, but one could be made. From my limited experimentation, I think it only adjusts the save file timestamp rather than the RTC itself. The in-game function only allows a single value to be changed, and I did some more experiments to figure out exactly what it does with that value. The “Please reset the time” screen initially shows the value of the “Previous time in game” from the prior screen, or “Time Passed” as A-Save calls it. After you choose a new value, the Time Passed is changed to that value, and the Initial Time is also changed to the current RTC value minus the Time Passed, so that the “Present time in game” is the same as the value you set.
I believe the actual RTC date is completely unchanged, but it would be best to confirm this on an actual cartridge. If you use this screen to change the time to something greater than the actual RTC value, then the Initial Time will become negative, because you’re saying that the save file was created before the RTC was (re)started. From what I can tell, the game still calculates the present time correctly when Initial Time is negative. Therefore, I don’t think it’s necessary to actually change the RTC in order to fix a new-battery save file; just running the in-game clock adjustment ought to cause time-based events to resume.