Hacking Homebrew Homebrew app [DEVLOG] TimeStranger-NX - First Native Save Editor for Digimon Story: Time Stranger w/ Direct NAND Injection (Sneak Peek)

cbreezy210

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Hey all! Long-time lurker, occasional poster here. I'm cbreezy210, previously known for releasing PKHeX-NX and ACNH-Save-Editor. Today, I'm thrilled to share a sneak peek at my newest passion project currently in heavy development: **TimeStranger-NX**.

This will be the **first-ever native homebrew save editor specifically for *Digimon Story: Time Stranger* running entirely on the Switch. But what truly sets it apart - and what consumed countless hours of reverse engineering - is its implementation of **Direct NAND Injection**.

Forget the old workflow: Dump → Edit on PC → Restore. Our tool interacts directly with the console's internal storage. It mounts the secure save partition, modifies values in real-time, and safely commits the changes back to the NAND. Zero bridges. Zero external dependencies beyond Atmosphere itself.

*(Note: This is a DEVLOG thread. A public v1.0.0 release with downloadable .nros is coming soon once core features are finalized!)*

🔍 Under the Hood: Overcoming Unique Challenges
Every game protects its saves differently. *Time Stranger's* architecture threw several curveballs that required innovative solutions:

1. **Locating the Ghost Partition:** Standard API calls returned empty directories. Through exhaustive recursive traversal and comparison against known good dumps, we isolated the live save container within nested subdirectories under `/savedata/`.

2. **Cracking Silent Data Loss:** Initial prototypes suffered from phantom writes—data seemed accepted by the FS layer but evaporated post-reboot. Forensic analysis revealed the culprit: failure to invoke `fsFsCommit(&saveFs)` after modifying files. This forces the volatile cache down to persistent media. Omitting this step results in complete rollback—a behavior notably absent in simpler targets like SV or NH.


3. **Dynamic Offset Mapping:** Rather than hardcoding addresses blindly, we integrated automated differential scanners capable of comparing two distinct states of a save blob to isolate mutated bytes corresponding

*Github page: https://github.com/cbreezy210/TimeStranger-NX *
 
Last edited by cbreezy210,
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Quick update this morning: Added auto-backup system with timestamped saves + emergency rollback feature ([ZL] button). Still hunting down item/monster stat offsets before v1.0.

If anyone has experience with Digimon save structures or wants to help reverse-engineer inventory tables, DM me or open an issue on the repo!

Thanks for the interest so far - TrunksSSJ23 appreciated the 👍!
 

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