Tool to modify the Nintendo DS hardware RTC

[MegaBoyEXE]

Hi, does anyone knows if there's any tool (NDS homebrew) available that allows modifications to the NDS RTC, without triggering the "anti time travel" feature that locks time events in Gen4 and Gen5 for 24h?

I can do this with Gen3 using either a GBA homebrew in EverdriveGBA or a NDS homebrew for original Gen3 carts.
I can also do this in 3DS using GodMode9 for 3DS Gen6 and Gen7 games.

But I never found a tool that actually do this for NDS RTC, the Gen4 and Gen5. That would be a NDS homebrew for R4 carts.

Thx!

Edited September 8, 2019 by MegaBoyEXE

[MegaBoyEXE]

As nobody seems to know of any tool around, I decided to create one myself.
I've used the "GBA rtcread" tool as base code for GUI, so if you used that tool before, you should be familiar with it.

Just be advised that you are responsible to sync the "week day" value too when changing the Date.

I was able to successfully do in-game events without penalties, like growing berries by changing time in increments of 4 hours, and saving again.

This tool changes the RTC without modifying the "RTC Offset" data in the firmware, so games cannot detect time changes.

Source code is included.

RTCChangerNDS.zip

[DeadSkullzJr]

Did a small update to the homebrew application. Also created an RTCChanger plugin icon for the SuperCard DSTWO.

Changelog:
v1.1.0 - September 22, 2019 (Updated by DeadSkullzJr)
- Added a new homebrew icon
- Added a new homebrew description

RTCChanger NDS (v1.1.0).7z RTCChanger NDS Plugin Icon (v1.0).7z

[MegaBoyEXE]

v1.1.1 - Fixed the day roll over when it is a leap year in February.

RTCChanger NDS (v1.1.1).7z

[DeadSkullzJr]

Another update!

Changelog:
v1.2.0 - September 23, 2019 (Updated by DeadSkullzJr)
- Tweaked some of the text
- Added the homebrew application version number to the title in the menu.

RTCChanger NDS (v1.2.0).7z