Hey all,
I've been trying to move my Steam save for Digimon Story: Time Stranger (currently testing with the demo, but hit the same issue on the full game) over to my modded Switch, and I've hit a wall that I think is a savedata-signing issue rather than a file-format one. Posting here in case anyone's cracked this for Time Stranger specifically, or has general insight.
Setup:
What I've tried:
What I've ruled out so far:
My working theory: The Switch's save-data system uses a signed/journaled container that JKSV can export the raw contents of, but not the actual signature — .nx_save_meta turned out to just be JKSV's own bookkeeping file (starts with a JKSV magic header), not a real console-level signature blob. So there's no accessible file to "fix" — the integrity check is presumably tied to the console's own keys at the OS level, similar to what I've seen described for other signed-savedata titles (Team Sonic Racing, etc.) where PC-originated save content is never accepted without the console itself having legitimately written it first.
Questions for the thread:
Happy to share more hex dumps / findings if it's useful — I've done a fair amount of digging into the save format itself already, just stuck on the container/signing layer.
Thanks in advance to anyone who's dealt with this.
I've been trying to move my Steam save for Digimon Story: Time Stranger (currently testing with the demo, but hit the same issue on the full game) over to my modded Switch, and I've hit a wall that I think is a savedata-signing issue rather than a file-format one. Posting here in case anyone's cracked this for Time Stranger specifically, or has general insight.
Setup:
- Steam version: 23514637
- Switch version: US, Ver. 1.2.1, CFW via [Atmosphère/etc.]
- Tools used: JKSV for export/import
What I've tried:
- Exported my Switch save folder with JKSV (savedata/0000, 0001, slot_0000, slot_0001, system_data, plus .nx_save_meta outside the savedata folder).
- Replaced the contents of savedata/ with the equivalent files from my Steam save folder.
- Re-imported with JKSV back onto the console.
- Result: "The save data list is corrupted."
What I've ruled out so far:
- This isn't a raw-copy mistake — I used JKSV's proper export/import round-trip, not a manual file swap.
- It's not a content/byte-format issue either: I compared the Steam and Switch save files directly. The main save data (0000/0001) uses AES-128-ECB encryption (confirmed via repeated ciphertext blocks — the same dominant 16-byte block shows up across saves and even inside system_data, meaning it's a single fixed key, not device-specific).
- Even when I tested with byte-for-byte identical file content between the two platforms, the import still corrupted. That rules out a data/offset mismatch — the failure is happening at a level above the actual save content.
My working theory: The Switch's save-data system uses a signed/journaled container that JKSV can export the raw contents of, but not the actual signature — .nx_save_meta turned out to just be JKSV's own bookkeeping file (starts with a JKSV magic header), not a real console-level signature blob. So there's no accessible file to "fix" — the integrity check is presumably tied to the console's own keys at the OS level, similar to what I've seen described for other signed-savedata titles (Team Sonic Racing, etc.) where PC-originated save content is never accepted without the console itself having legitimately written it first.
Questions for the thread:
- Has anyone gotten Time Stranger saves working cross-platform at all (I know this game doesn't officially support crosssaves which is why I am using modded Switch ↔ PC)?
- If you've solved this for a similarly signed-savedata game, what was actually different about your approach — did you find a way to get PC content accepted, or did it end up being "start on Switch, then edit in place" instead?
- Is anyone aware of whether Time Stranger's system_data file (~672 bytes on Switch, looks like plain uncompressed integer fields — no encryption at all) holds anything relevant to save-slot validation that might matter here?
Happy to share more hex dumps / findings if it's useful — I've done a fair amount of digging into the save format itself already, just stuck on the container/signing layer.
Thanks in advance to anyone who's dealt with this.
