[Bug] NSOs with ZBIC compression (NsoFlags_UseZbicCompression) fail to load

[Appealpotato]

Prerequisites

• I am confident that my issue has not been reported already in open OR closed issues.
• I am able to reliably reproduce the issue on the latest stable or canary version.
• I am not using an unofficial build (Flatpak, Emudeck, etc.).
• I am a silly goose and didn't read these boxes.
• I am a silly goose and DID read these boxes.

Description of the issue

Environment

• Ryujinx Canary 1.3.351 (2026-08-26) — latest as of 2026-09-01
• OS: Windows x64
• Firmware installed in Ryujinx: 22.1.0
• Game: Can I Not Fall for Idols? (アイドルと〇〇しちゃダメですか) — [0100C6B028F38000][v0][BASE] (eShop, released 2026-08-27)

Symptom

The game fails to load immediately:

Unhandled exception caught: System.ArgumentOutOfRangeException: srcOffset ('-38731')
   at Lz4.Decompress ... NsoReader.ReadSegmentImpl ... NsoExecutable.DecompressSection

The main NSO cannot be loaded by LibHac's NSO reader.

Root cause

This title is built with FS SDK 22.2.0 and its main NSO uses the new ZBIC compression (modified Zstandard) instead of LZ4 for its segments.

NSO flags of the shipped main: 0xBF (0b10111111), which includes NsoFlags_UseZbicCompression = BIT(7) (naming per nxdumptool's nso_zbic.h):

NsoFlags_TextCompress       = BIT(0)
NsoFlags_RoCompress         = BIT(1)
NsoFlags_DataCompress       = BIT(2)
NsoFlags_TextHash           = BIT(3)
NsoFlags_RoHash             = BIT(4)
NsoFlags_DataHash           = BIT(5)
NsoFlags_ExecuteOnlyMemory  = BIT(6)
NsoFlags_UseZbicCompression = BIT(7)

LibHac's NSO reader has no ZBIC handling: when bit 7 is set it still tries to LZ4-decompress the segment, which fails with the srcOffset exception above.

Notes

• Only main uses ZBIC in this title. rtld, sdk, subsdk0, subsdk1 all use flags 0x3F (plain LZ4 + hash checks) and load fine.
• nxdumptool already implements ZBIC decompression (nso_zbic.c/h, ZSTD with decompression margin) — useful as a reference.
• Workaround for testing: decompress the ZBIC segments, rebuild main as an uncompressed NSO (flags 0x38 = no compression + hash checks on; segment content verified against the SHA-256 hashes baked in the NSO header) and replace ExeFS via a mod exefs.nsp. With that workaround the game loads fully — but then hits a second, separate crash (see the SDK 22.2.0 module-init issue).

Expected behavior

NSOs with NsoFlags_UseZbicCompression should be decompressed with Zstandard (or the appropriate ZBIC variant) instead of LZ4.

Reproduction steps

• Launch game normally through the emulator.
• It crashes before even getting to the boot screen.

Log file

Ryujinx_Canary_1.3.351_2026-09-01_14-04-46.log

OS

Windows 10 x64

Ryujinx version

1.3.351, Canary

Game version

No response

CPU

Ryzen 5600x

GPU

RTX 3060Ti

RAM

32GB

List of applied mods

No response

Additional context?

No response

[GreemDev]

Did you use AI to help write this issue?

[Appealpotato]

Why ask a question where both answers are read the same? Anyway:

Nintendo seems to have introduced a new ZBIC compression format. I decompressed it, then proved that my version is identical to what the hardware (physical Switch console) loads, byte for byte, verified by the cryptographic hash.

Then with the patch the game actually reaches the loading screen, then crashes at a specific place. The first time the SDK tries to allocate memory (during the early initialization of the sdk module), before the actual game code even starts up.

I tested the patch on my own modded Switch and it runs fine, so the game isn't a bad dump, or the patch is bad. The emulator seems to not handle something about the new SDK 22.2.0 environment.

I also dug into the crash on the emulator's side; the allocator state, mutex, GOT, and the 3 GiB heap region are all intact and writable, so it's not memory corruption. The SDK is aborting on something about the environment it doesn't like.

Here's the log (from my makeshift build, the only change is a debug probe in the Break handler, gated to this title's ID):

Ryujinx_1.0.0-dirty+475615f0431b4995b03c930c5089d20f6f3570e0_2026-09-01_23-15-58.log

[GreemDev]

Why ask a question where both answers are read the same?

What? Just answer the question.

[saman-boop]

Why ask a question where both answers are read the same?

What? Just answer the question.

Just fix the issues.

[LordBubblesDev]

Just fix the issues.

Nobody pays the devs, and they contribute of their own free will. But I would vote for not fixing it considering users like you feel entitled enough to think you're owed a fix.

[saman-boop]

Just fix the issues.

Nobody pays the devs, and they contribute of their own free will. But I would vote for not fixing it considering users like you feel entitled enough to think you're owed a fix.

I am just tired of these pretentious modding AI luddites and their simps wanting everyone to worship their manual labor. Get it going already and shut up.

[LordBubblesDev]

I am just tired of these pretentious modding AI luddites and their simps wanting everyone to worship their manual labor. Just get it going already and shut up.

And perhaps we're tired of users who think every hobbyist developper owes them free and maintained open source software.

[saman-boop]

I am just tired of these pretentious modding AI luddites and their simps wanting everyone to worship their manual labor. Just get it going already and shut up.

And perhaps we're tired of users who think every hobbyist developper owes them free and maintained open source software.

Sorry all those AI models allowed all of us peasants easy access to get help with whatever we need, instead of personally begging your type for assistance, so you could feel good about yourselves.

Why don't you close your open source software and shut it all down? Good luck!

[LordBubblesDev]

Sorry all those AI models allowed all of us peasants easy access to get help with whatever we need, instead of personally begging your type for assistance, so you could feel good about yourselves.

You seem to be mistaken into believing that we provide assistance. For that, you'd need to join the discord and go through the verification process so that we can ensure you are not using the emulator for piracy. This surely gives us peace considering how little time we need to spend on helping the few that get verified.

[saman-boop]

Sorry all those AI models allowed all of us peasants easy access to get help with whatever we need, instead of personally begging your type for assistance, so you could feel good about yourselves.

You seem to be mistaken into believing that we provide assistance. For that, you'd need to join the discord and go through the verification process so that we can ensure you are not using the emulator for piracy. This surely gives us peace considering how little time we need to spend on helping the few that get verified.

If it gave you the peace you wanted, then you wouldn't be crying so much over peasants using AI for whatever reason to fix their apps, or games, or githubs.

Go be brave, shut down Ryubing entirely, hero.

[LordBubblesDev]

If it gave you the peace you wanted, then you wouldn't be crying so much over peasants using AI for whatever reason to fix their apps, or games, or githubs.

Funnily enough, we don't really care that users do that. We just won't participate :))