3DSlibris

3DSlibris
General
Author	Rigle
Type	Utilities
Version	2.0.4
License	GPL-2.0
Last Updated	2026/04/03
Links
Download
Website
Source

Nintendo 3DS homebrew ebook reader based on the original Nintendo DS project dslibris.

3dslibris ports the original architecture to libctru, keeps the fast text-first reading model, and adds practical 3DS UX improvements (grid library, cover thumbs, indexed navigation, procedural UI skin, orientation-aware touch, etc.).

The current .cia packaging flow is based on the same makerom/bannertool process used by Universal-Updater, adapted to this project's assets and release layout.

Features

• Custom fonts.
• Bookmarks.
• Table of contents/index support.
• Left- and right-handed layouts.
• Three color modes: Daylight, Night, and Book.
• Strong EPUB support.
• Good FB2, TXT, RTF and ODT support.
• Experimental MOBI support.
• PDF, CBZ, and XPS viewing (MuPDF-backed).

Installation

Recommended install:

• Download 3dslibris-sdmc.zip from GitHub Releases.
• Extract that zip into the root of your SD card, so it expands into sdmc:/.
• Put your books in sdmc:/3ds/3dslibris/book/.
• Launch sdmc:/3ds/3dslibris/3dslibris.3dsx from Homebrew Launcher.

Alternative install:

• Install 3dslibris.cia.
• Launch the installed title once so it creates sdmc:/3ds/3dslibris/ if needed.
• Put your books in sdmc:/3ds/3dslibris/book/.
• Launch the installed title.

Important:

• The .cia bundles the default font/ and resources/ runtime assets inside RomFS, so it can boot without manually extracting 3dslibris-sdmc.zip.
• Books are discovered from sdmc:/3ds/3dslibris/book/ and romfs:/3ds/3dslibris/book/.
• If the same filename exists in both places, SD takes priority.
• 3dslibris-sdmc.zip is still the recommended install for .3dsx, and it remains useful if you want the same runtime files laid out explicitly on SD.
• 3dslibris-debug.3dsx uses the same SD layout and writes verbose diagnostics to sdmc:/3ds/3dslibris/3dslibris.log.
• The .cia build uses the Universal-Updater-style packaging flow and now also validates the bundled RomFS path in GitHub Actions.

Generated install package targets:

• make package-sdmc stages dist/sdmc/... with 3dslibris.3dsx included
• make zip-sdmc creates dist/3dslibris-sdmc.zip
• make cia creates 3dslibris.cia
• make source-release creates dist/3dslibris-source.tar.gz
• GitHub Releases: pushing a tag like v2.0.4 triggers .github/workflows/release.yml and attaches 3dslibris.cia, 3dslibris.3dsx, 3dslibris-debug.3dsx, dist/3dslibris-sdmc.zip, and dist/3dslibris-source.tar.gz to the release

Bundled runtime files:

• sdmc/3ds/3dslibris/resources/splash.jpg
• sdmc/3ds/3dslibris/resources/ui/icons/png/*.png
• sdmc/3ds/3dslibris/book/README.md
• sdmc/3ds/3dslibris/font/README.md
• sdmc/3ds/3dslibris/font/Liberation*.ttf
• sdmc/3ds/3dslibris/font/OFL-1.1.txt

Notes:

• Homebrew Launcher path: keep the app at sdmc:/3ds/3dslibris/3dslibris.3dsx
• Debug build path: keep 3dslibris-debug.3dsx in the same sdmc:/3ds/3dslibris/ folder if you want verbose logs
• Default Liberation fonts are bundled in the SD package for .3dsx, and inside RomFS for .cia
• You can replace them with other .ttf, .otf, or .ttc fonts if you want to customize the reading/UI typefaces
• Runtime files such as 3dslibris.xml, 3dslibris.log, and cache/* are created by the app on first run

sdmc:/3ds/3dslibris/3dslibris.3dsx
sdmc:/3ds/3dslibris/book/*.epub|*.fb2|*.txt|*.rtf|*.odt|*.mobi
sdmc:/3ds/3dslibris/font/*.ttf
sdmc:/3ds/3dslibris/resources/splash.jpg
sdmc:/3ds/3dslibris/resources/ui/icons/png/{back,gear,home,next,prev}.png

Supported formats

Strong support

• EPUB (EPUB2 + EPUB3 NAV/NCX parsing with robust fallbacks)

Good support (text-oriented)

• FB2
• TXT
• RTF
• ODT

Experimental / best-effort

• MOBI
  • First open can be slow on large books (decompress + parse + pagination)
  • Subsequent opens are accelerated by persistent page cache
  • TOC quality is heuristic for many files (can be approximate)
  • Inline MOBI images now reuse the same smart inline / band / page layout pipeline used by EPUB/FB2, with better caption flow on mixed photo spreads
  • Includes an optional per-book line wrap fix for badly converted files that hard-wrap prose line by line, while preserving embedded image markers during cleanup
  • Empty or corrupt books are reported with a readable error instead of a raw numeric code
• PDF
  • Viewer-only path with MuPDF-backed rendering
  • Top screen shows a zoomed page region; bottom screen shows the full-page preview and viewport box
  • Uses the shared fixed-layout reader controls documented below
  • PDF-enabled builds in this branch are distributed with AGPL-driven notice and source-release requirements; see the license section below
• CBZ
  • Viewer-only path with MuPDF-backed image-page rendering
  • Uses the shared fixed-layout reader controls documented below
• XPS
  • Viewer-only path with MuPDF-backed rendering
  • Uses the shared fixed-layout reader controls documented below

Known limitations

• Some EPUB files have malformed anchors; index jumps can be approximate when source metadata is broken.
• MOBI TOC extraction depends on file structure and may omit or merge entries in some books.
• MOBI inline images depend on recoverable image references in the source markup, including the zero-padded recindex values commonly found in Kindle-generated books; malformed files can still miss some images.
• Some malformed MOBI sources still contain encoding or OCR artifacts that cannot be repaired reliably on the reader side.
• After changing font size, paragraph spacing, orientation, reading fonts, or the per-book MOBI line wrap fix, reopen the current book to apply the new layout.
• Reading position and existing bookmarks are remapped approximately after that reopen and can shift a few pages from their original location.
• No DRM support.

Controls

Library controls

D-Pad - Move the current selection around the library grid

A - Open the selected book

L / R - Jump to the previous or next library page

Touch - Tap a book to select it, tap it again to open it

Y / Select - Open settings

Default reading controls

A/B/L/R - Turn pages

D-Pad Left/Right - Jump between bookmarks

Y - Toggle bookmark

X - Change background color

Select - Settings

Start - Return to library

Touch UI for library, settings, index, bookmarks, font menus...

PDF / CBZ / XPS controls

A - Zoom in

B - Zoom out

Left/Right - Previous or next page

Up/Down - Next or previous chapter when the document exposes an outline; otherwise previous or next page

Touch - Move the viewport by tapping or dragging on the page preview

Select - Open settings

Start - Return to library

Screenshots

Changelog

v2.0.4

• Highlights
  • Bookmarks and last-read page persistence fixed: prefs XML writing now escapes attribute values correctly and sanitizes invalid control characters, so filenames like ... & ... no longer break 3dslibris.xml parsing on startup.
  • CIA library source handling improved: the app now discovers books from both sdmc:/3ds/3dslibris/book and romfs:/3ds/3dslibris/book, with SD entries taking priority when names overlap.
  • Left-handed page screen order corrected: reflow reading now inverts first and second reading screens correctly in left-handed orientation.
  • Orientation-relative library D-Pad navigation: grid navigation now follows console orientation in both modes so directional input matches visual movement in right-handed and left-handed layouts.
  • Startup diagnostics improved: prefs load failures are now logged with an explicit warning instead of failing silently.
  • EPUB emphasis compatibility improved: the parser now recognizes bold/italic expressed via common style and class CSS patterns, not only semantic tags.
  • Release pipeline stability improved: debug MOBI builds now include the correct reporter definitions so debug-3dsx compiles reliably in CI/release workflows.

v2.0.3

• Highlights
  • Fixed bundled RomFS for .cia builds — the installable build now actually includes its bundled fonts and UI resources, instead of staging them locally but omitting them from the final CIA package.
  • Fixed the CIA-only startup crash — a null cache entry in the text/font teardown path could trigger an ARM11 data abort during early startup failure; font initialization and cache cleanup are now hardened.
  • Better runtime asset fallback — bundled fonts and resources are resolved safely between SD and RomFS, so .cia installs no longer depend on a manual font/ or resources/ copy to boot.
  • Stable fatal boot screens — missing-book and startup error screens no longer flicker between old and new frames while waiting for Start.
  • Clearer first-run behavior — if no books are present, the app now shows a stable message telling you to copy your EPUB, FB2, TXT, RTF, or ODT files into sdmc:/3ds/3dslibris/book.
  • CIA build validation added to CI — GitHub Actions now builds and verifies the .cia path as well, including checks that the staged RomFS contains the bundled runtime files.
• Included reader functionality
  • MuPDF-backed PDF, CBZ, and XPS support
  • Progressive fixed-layout rendering
  • Asynchronous/deferred MOBI open on New 3DS
  • Generated library cover thumbnails
  • Bundled runtime assets for .cia installs

v2.0.2

• Highlights
  • Fixed CIA startup on hardware and Azahar: the packaged NCCH code is now emitted without compression, avoiding the startup crash seen in previous 2.0.1 CIA builds.
  • No change to reader features: this is a packaging-focused release intended to restore a working installable build.
  • Clean CIA build path: the local CIA build also includes the small book_io.cpp declaration fix required for a clean rebuild.

v2.0.1

• Highlights
  • Full branch catch-up release: v2.0.1 includes the missing commits that were finished after the original v2.0.0 tag, so the public release now matches the maintained main line.
  • Centralized runtime paths: SD, cache, and related filesystem paths now live in a shared path layer instead of being duplicated across subsystems.
  • Cleaner repo structure: shared helpers were reorganized, legacy duplicate files were removed after the move, and bundled expat sources now live under third_party/.
  • MOBI cache code split out cleanly: page-cache serialization and invalidation logic now live in a dedicated MOBI cache module instead of being embedded in the larger common book I/O unit.
  • Improved native test ergonomics: the text-layout and Unicode tests now reuse a shared native build helper instead of each script compiling the same dependency objects manually.
  • Expanded technical documentation: the repository now includes architecture notes plus local NDS/3DS hardware reference material derived from GBATek for future maintenance work.
• Included reader functionality (from the v2.0.0 line)
  • MuPDF-backed PDF, CBZ, and XPS support
  • Progressive fixed-layout rendering with preview-first display
  • Asynchronous/deferred MOBI open on New 3DS
  • Generated library cover thumbnails for EPUB, FB2, MOBI, PDF, and CBZ
  • Bundled runtime assets for .cia installs

v2.0.0

• Highlights
  • PDF, CBZ, and XPS reading: open PDF documents, comic books (CBZ), and XPS files with zoom, full-page preview on the bottom screen, and outline navigation when available.
  • Progressive page loading: a preview of the page is shown immediately, then it refines to full quality in the background.
  • Faster on New 3DS: page rendering for PDF and CBZ runs on a separate processor core, keeping the UI responsive. Old 3DS still works with automatic fallback.
  • MOBI books open without freezing the UI on New 3DS thanks to asynchronous processing: you can start reading while the rest of the book finishes loading in the background.
  • Library covers now work for every format: EPUB, FB2, MOBI, PDF, and CBZ all show actual page thumbnails instead of placeholders.
  • All 1.1.x improvements included: inline images in MOBI and EPUB, faster image-heavy books, better text rendering, and more accurate MOBI table of contents.
  • No more manual SD card setup for .cia installs: fonts and UI resources are built in.
  • More stable startup: problematic MOBI files no longer cause crashes, and the app stays on a clear error screen instead of flickering between states when something goes wrong.

v1.1.0

• Highlights
  • Library navigation: you can now move the selection around the book grid with the D-Pad and press A to open.
  • Images inside EPUB and MOBI books now display correctly: small icons, wide separators, and full-size figures no longer take up the entire screen or disappear.
  • EPUB books with lots of images open noticeably faster thanks to internal optimizations in how images are loaded from the archive.
  • Library cover thumbnails for MOBI books generate faster on subsequent visits since cover data is now remembered between sessions.
  • No more manual SD card setup for .cia installs: the .cia now includes all required fonts and UI resources, so a plain install from the Homebrew Menu is enough.
  • Better text rendering across all formats: improved line breaking, proper handling of special characters, and font sizes that can no longer be set to values that break pagination.
  • Code blocks and <code></code> <pre></pre> sections in EPUBs now wrap properly instead of running off the edge of the screen.
  • MOBI books benefit from multiple fixes: more accurate table of contents, better plain-text wrapping that matches how real books read, and support for HUFF/CDIC compressed files.

v1.0.3

• Highlights
  • Pressing right on settings rows such as font size and paragraph spacing now increases the value.
  • Pressing left now decreases the value, matching the on-screen arrows and touch layout.
  • Horizontal navigation inside the settings list is aligned with the same left/right direction.
  • The main browser splash now shows the app version centered at the bottom of the left screen.
  • Changing font size, paragraph spacing, orientation, or reading fonts no longer tries to repaginate the book inside the settings menu.
  • When layout-related settings change, the app shows a warning and applies the new layout after reopening the current book.
  • MOBI parsing is more resilient against empty or corrupt files and now shows a readable error instead of a raw numeric failure.
  • MOBI books now have an optional per-book line wrap fix for badly converted files that hard-wrap normal prose into many short blocks.
  • The .cia packaging flow was rebuilt around the same makerom/bannertool process used by Universal-Updater.
  • Previous 1.0.3 test .cia builds could install but fail to boot because the packaged exheader ended up with an invalid main-thread priority.
  • The generated .cia now boots correctly on original hardware and in Azahar.
• Known bug
  • When a book is reopened after a layout change, or after toggling the per-book MOBI line wrap fix, reading position and existing bookmarks are remapped approximately and may land a few pages away from their original location.
  • Some malformed MOBI files still contain source encoding or OCR artifacts that cannot be repaired fully by the reader.

v1.0.2

• Highlights
  • Startup now stops with clear install guidance if required runtime files are missing from the SD card.
  • The error message tells users to download and extract 3dslibris-sdmc.zip and shows the expected sdmc:/3ds/3dslibris/ layout.
  • The README now explains installation step by step for the .3dsx + SD package flow.

v1.0.1

• Highlights
  • EPUB cold opens are now much faster on large books by indexing ZIP entries before spine parsing.
  • In real tests with Don Quijote, cold open time dropped from about 50.5s to about 7.2s, roughly a 7x improvement.
  • Releases now include 3dslibris-debug.3dsx, which enables verbose diagnostic logging in 3dslibris.log.
• Notes
  • The debug build is intended for troubleshooting and performance investigation.
  • EPUB TOC resolution remains separate from the main open path and was not the main cause of the previous cold-open slowdown.

v1.0.0

• First release.

Credits

• Original dslibris: Ray Haleblian
• 3DS port and maintenance: Rigle

External links

• GitHub - https://github.com/RigleGit/3dslibris
• GBAtemp - https://gbatemp.net/threads/release-ebook-reader-for-nintendo-3ds-3dslibris-dslibris-port.680297/