3DSlibris

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

Known issues

https://github.com/RigleGit/3dslibris/issues

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