Technical notes
Citra fork, renamed Mandarine-Neo at release 1.3.0. External files live in
sysdata/ and nand/ under the user directory: user/ next to the executable when
that directory exists, otherwise Mandarine on Windows and macOS and
mandarine-emu on Linux, with Citra and citra-emu kept as legacy locations.
ref: src/common/common_paths.h:16-70, src/common/file_util.cpp:770-839
InitKeys reads boot9.bin then aes_keys.txt. Encrypted content needs one of the
two; a ROM without crypto reads neither.
ref: src/core/hw/aes/key.cpp:315-324, src/core/file_sys/ncch_container.cpp:200-210
Failure to derive a key or to find a seed marks the content undecryptable and
loading stops with ErrorEncrypted.
ref: src/core/file_sys/ncch_container.cpp:219-223, src/core/file_sys/ncch_container.cpp:236-280, src/core/file_sys/ncch_container.cpp:347-349
System archives resolve to the NAND title tree. Shared font, Mii data, country
list and bad word list fall back to open-source replacements built into the
binary when the title is absent.
ref: src/core/file_sys/archive_ncch.cpp:126-179, externals/open_source_archives/Readme.md
The embedded shared font only answers title low ID 0x00014002. CHN, KOR and TWN
resolve to 0x00014102, 0x00014202 and 0x00014302, which fall through to
shared_font.bin and then to ErrorSystemFiles, reported as recoverable.
ref: src/core/hle/service/apt/apt.cpp:195-213, src/core/hle/service/apt/apt.cpp:276-291, src/mandarine_qt/main.cpp:3209-3215
ClCertA is read from NAND title 0x0004001B00010002 and its ctr-common-1-cert.bin
and ctr-common-1-key.bin members are decrypted with the KeySlot 0x0D normal key.
Both the title and the key slot are needed for authenticated HTTPS.
ref: src/core/hle/service/http/http_c.cpp:1963-2036
System titles are downloaded and installed in-app from the Nintendo CDN, so the
NAND title tree is not user-supplied.
ref: src/mandarine_qt/configuration/configure_system.cpp:672-678, src/core/hle/service/am/am.cpp:536, src/core/nus_download.cpp:12-13
DumpKeys.gm9, a GodMode9 script producing aes_keys.txt and seeddb.bin, ships in
the tree and documents sysdata/ as their destination.
ref: dist/dumpkeys/README.md, dist/dumpkeys/DumpKeys.gm9
The plugin loader scans sdmc/luma/plugins/
/ for any .3gx file and
falls back to sdmc/luma/plugins/default.3gx. Plugins carry no fixed identity.
ref: src/core/hle/service/plgldr/plgldr.cpp:112-146</p>
<p>mcu.dat holds per-installation MCU state that the emulator writes itself when
the file is absent or carries the wrong magic.
ref: src/core/hle/service/cfg/cfg.cpp:734-756, src/core/hle/service/cfg/cfg.h:425-439</p>
<p>sector0x96.bin is defined but read by no code path.
ref: src/common/common_paths.h:70</p>
</details>
<p><strong>7 files</strong> | 0 required, 7 optional | 7 in repo, 0 missing | 1 with HLE fallback</p>
<div class="rb-file-entry rb-file-entry-optional">
<p><strong><code>boot9.bin</code></strong> <span class="rb-badge rb-badge-muted">optional</span> <span class="rb-badge rb-badge-success">in repo</span></p>
<ul>
<li>Path: <code>sysdata/boot9.bin</code></li>
<li>System: <a href="../../systems/nintendo/#3ds">nintendo-3ds</a></li>
<li>Size: 64.0 KB</li>
<li>Validation: size</li>
<li>Source: <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hw/aes/key.cpp#L137-L206"><code>src/core/hw/aes/key.cpp:137-206</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hw/rsa/rsa.cpp#L49-L80"><code>src/core/hw/rsa/rsa.cpp:49-80</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/common/common_paths.h#L69"><code>src/common/common_paths.h:69</code></a></li>
<li>AES key section read at offset 55760, RSA modulus and exponent at 0xB3E0 and 0xB4E0</li>
</ul>
</div>
<div class="rb-file-entry rb-file-entry-optional">
<p><strong><code>aes_keys.txt</code></strong> <span class="rb-badge rb-badge-muted">optional</span> <span class="rb-badge rb-badge-success">in repo</span></p>
<ul>
<li>Path: <code>sysdata/aes_keys.txt</code></li>
<li>System: <a href="../../systems/nintendo/#3ds">nintendo-3ds</a></li>
<li>Source: <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hw/aes/key.cpp#L208-L311"><code>src/core/hw/aes/key.cpp:208-311</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/common/common_paths.h#L68"><code>src/common/common_paths.h:68</code></a></li>
<li>Platforms: <a href="../../platforms/bizhawk/">bizhawk</a>, <a href="../../platforms/emudeck/">emudeck</a>, <a href="../../platforms/retrodeck/">retrodeck</a></li>
<li>key slots, common keys, DLP and NFC key Ys and NFC secrets, one per line</li>
</ul>
</div>
<div class="rb-file-entry rb-file-entry-optional">
<p><strong><code>seeddb.bin</code></strong> <span class="rb-badge rb-badge-muted">optional</span> <span class="rb-badge rb-badge-success">in repo</span></p>
<ul>
<li>Path: <code>sysdata/seeddb.bin</code></li>
<li>System: <a href="../../systems/nintendo/#3ds">nintendo-3ds</a></li>
<li>Source: <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/file_sys/seed_db.cpp#L12-L58"><code>src/core/file_sys/seed_db.cpp:12-58</code></a></li>
<li>Platforms: <a href="../../platforms/bizhawk/">bizhawk</a></li>
<li>game seed database for 9.6+ titles; an empty database is written when the file is absent</li>
</ul>
</div>
<div class="rb-file-entry rb-file-entry-optional">
<p><strong><code>shared_font.bin</code></strong> <span class="rb-badge rb-badge-muted">optional</span> <span class="rb-badge rb-badge-success">in repo</span> <span class="rb-badge rb-badge-info">HLE fallback</span></p>
<ul>
<li>Path: <code>sysdata/shared_font.bin</code></li>
<li>System: <a href="../../systems/nintendo/#3ds">nintendo-3ds</a></li>
<li>Source: <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/apt/apt.cpp#L254-L270"><code>src/core/hle/service/apt/apt.cpp:254-270</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/common/common_paths.h#L67"><code>src/common/common_paths.h:67</code></a></li>
<li>legacy path, tried after the shared font system archive; decompressed BCFNT with the 0x80 byte APT header</li>
</ul>
</div>
<div class="rb-file-entry rb-file-entry-optional">
<p><strong><code>CTCert.bin</code></strong> <span class="rb-badge rb-badge-muted">optional</span> <span class="rb-badge rb-badge-success">in repo</span></p>
<ul>
<li>Path: <code>sysdata/CTCert.bin</code></li>
<li>System: <a href="../../systems/nintendo/#3ds">nintendo-3ds</a></li>
<li>Size: 384 B</li>
<li>Validation: size</li>
<li>Source: <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/am/am.cpp#L2427-L2454"><code>src/core/hle/service/am/am.cpp:2427-2454</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/am/am.cpp#L83-L93"><code>src/core/hle/service/am/am.cpp:83-93</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/am/am.h#L95"><code>src/core/hle/service/am/am.h:95</code></a></li>
<li>console client certificate; signature type must be 0x010005 and the issuer one of the two Nintendo CA G3 strings. The certificate here is assembled from a console OTP: signature and expiry read at 0x44 and 0x20, public key derived from the private key at 0x24 over sect233r1, and the whole body checked against Nintendo's root public key</li>
</ul>
</div>
<div class="rb-file-entry rb-file-entry-optional">
<p><strong><code>SecureInfo_A</code></strong> <span class="rb-badge rb-badge-muted">optional</span> <span class="rb-badge rb-badge-success">in repo</span></p>
<ul>
<li>Path: <code>nand/rw/sys/SecureInfo_A</code></li>
<li>System: <a href="../../systems/nintendo/#3ds">nintendo-3ds</a></li>
<li>Size: 273 B</li>
<li>Validation: size</li>
<li>Source: <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/cfg/cfg.cpp#L608-L610"><code>src/core/hle/service/cfg/cfg.cpp:608-610</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/cfg/cfg.cpp#L689-L709"><code>src/core/hle/service/cfg/cfg.cpp:689-709</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/cfg/cfg.h#L180-L186"><code>src/core/hle/service/cfg/cfg.h:180-186</code></a></li>
<li>console region and serial number; loaded on a size check alone, and paired with LocalFriendCodeSeed_B</li>
</ul>
</div>
<div class="rb-file-entry rb-file-entry-optional">
<p><strong><code>LocalFriendCodeSeed_B</code></strong> <span class="rb-badge rb-badge-muted">optional</span> <span class="rb-badge rb-badge-success">in repo</span></p>
<ul>
<li>Path: <code>nand/rw/sys/LocalFriendCodeSeed_B</code></li>
<li>System: <a href="../../systems/nintendo/#3ds">nintendo-3ds</a></li>
<li>Size: 272 B</li>
<li>Validation: size</li>
<li>Source: <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/cfg/cfg.cpp#L604-L606"><code>src/core/hle/service/cfg/cfg.cpp:604-606</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/cfg/cfg.cpp#L711-L732"><code>src/core/hle/service/cfg/cfg.cpp:711-732</code></a>, <a href="https://github.com/ptyfyre/mandarine-neo/blob/7f8ec960b6183be4350bca099d23ddd9fc7bcaa3/src/core/hle/service/cfg/cfg.h#L188-L193"><code>src/core/hle/service/cfg/cfg.h:188-193</code></a></li>
<li>friend code generation seed; loaded on a size check alone, and paired with SecureInfo_A</li>
</ul>
</div>
<p><em>Generated on 2026-08-23T16:12:06Z</em></p>
</article>
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