Kobalt v1.0-beta.3

What's new

• New option: Hide non-linear fragments, in Settings > Advanced. Normal page turns skip the optional sections of an EPUB, while links, Chapters and page numbers can still open them. It is off by default.

• Text size now goes up to 48 pt, from 20 pt, and Thickness up to +12, from +8.

• Automatic brightness, on Kobo devices with an ambient light sensor. Adjusting the brightness yourself turns it off.

• Kobo devices with an orientation sensor offer Portrait, Landscape and Both. Portrait is the default. Devices without a sensor keep manual rotation.

• On the Kobo Touch, the physical Home button saves your progress and returns to Kobo's Home screen.

• Page buttons turn the pages of Chapters, Bookmarks, search results and licenses.

• Fonts you add in subfolders of fonts/, such as fonts/Family/static/, appear in the font picker.

• Hyphenation for Estonian, Finnish, Georgian, Hungarian, Latvian, Lithuanian, Polish, Slovak, Slovenian and Ukrainian.

What's fixed

• More EPUBs open correctly, including books with imperfect markup, unsupported layout features or Adobe page templates.

• The screen flashes less often, and the font and layout panels open much faster.

• Reading progress is saved to Kobo every 30 seconds and before the device sleeps or connects over USB, so the sleep screen shows where you are.

• Fixed bugs syncing reading progress to Kobo for some KEPUB books, and opening books from compatible sync servers.

• Stats shows word counts for every book, plain EPUBs included, on Kobo and Android. Very long chapters no longer draw a line through their bar in the chart.

• With Publisher Fonts and a book without embedded fonts, serif text uses Libron, sans-serif uses Legible Next and monospace uses IBM Plex Mono.

• Formatting warnings appear only for layout features that are really unsupported, and no longer appear for large books just because of their size.

• The loading screen appears at once when you open a book, so opening feels faster and no longer looks frozen.

Installation

Download the package for your Kobo firmware:

• Kobalt-qt5.zip for firmware 4.38 and later.
• Kobalt-qt6.zip for firmware 5.18 and later 5.x, and 6.x.

Manual instructions

1. Connect your Kobo over USB and extract the ZIP on your computer. Show hidden files to see .adds and .kobo.
2. Copy .adds to the root of the Kobo drive. Merge folders and replace matching package files. Keep other apps, settings and reading data.
3. Then copy .kobo to the same drive root, merging folders again.
4. Eject the Kobo safely, disconnect USB and let the update install.

Copy both folders in that order. Leave the .tgz file inside .kobo compressed.

Checksums · Build information

Source code and dependencies

Kobalt v1.0-beta.2

What's new

• Added evenly spaced line-spacing slider marks with snapping at 100%, 110%, 120%, 130%, 140%, 150%, 175%, 200%, 250% and 300%. Plus and minus still adjust spacing by one percentage point.

What's fixed

• Fixed opening and appearance previews for EPUBs whose structural CSS selectors require styles to be recalculated after parsing. Publisher image spacing and centered text are preserved.

• Fixed opening EPUBs with repeated identical manifest items. Conflicting duplicate IDs remain unsupported.

• Fixed opening EPUBs with standard IDPF-obfuscated embedded TrueType or OpenType fonts.

• Fixed line spacing being applied twice. 150% now means 1.5 times the font size. Existing book settings are converted to preserve their approximate spacing, with 122% becoming 150% and a maximum of 300%.

• Fixed left alignment and justification moving publisher-centered text to the left.

• Fixed reversed landscape touch targets on affected Clara devices with firmware 4, using NickelRotate’s coordinate correction.

• Fixed opening and saved chapter lookup for sideloaded filenames containing #, ? or literal percent escapes on firmware 4. If files fail to open, an explanation is logged.

• Fixed opening DRM-free local EPUBs regardless of their folder, including hidden folders, SD storage, Dropbox, Google Drive and third-party sync services. Protected books still open in the built-in reader.

• Fixed missing Chinese, Japanese, Korean and other bundled fallback characters in chapter titles and interface controls. CJK fallback text and CFF font previews use Kobalt’s font renderer to avoid crashes in the firmware font driver.

• Load private interface fallback fonts when text first needs them, including the CJK collection. This is more memory efficient.

• Fixed Kobalt remaining inactive when Nickel's initialization callback was missed.

Installation

Download the package for your Kobo firmware:

• Kobalt-qt5.zip for firmware 4.38 and later.

Manual instructions

1. Connect your Kobo over USB and extract the ZIP on your computer. Show hidden files to see .adds and .kobo.
2. Copy .adds to the root of the Kobo drive. Merge folders and replace matching package files. Keep other apps, settings and reading data.
3. Then copy .kobo to the same drive root, merging folders again.
4. Eject the Kobo safely, disconnect USB and let the update install.

Copy both folders in that order. Leave the .tgz file inside .kobo compressed.

Checksums · Build information

Source code and dependencies

Kobalt v1.0-beta.1

First public Kobo beta, using Qt5 on firmware 4.38 and later. Kobalt should work on most devices, but devices older than 10 years might run into issues with memory. Try it out and let me know if Kobalt worked well on your device!

Installation

Download the package for your Kobo firmware:

• Kobalt-qt5.zip for firmware 4.38 and later.

Manual instructions

1. Connect your Kobo over USB and extract the ZIP on your computer. Show hidden files to see .adds and .kobo.
2. Copy .adds to the root of the Kobo drive. Merge folders and replace matching package files. Keep other apps, settings and reading data.
3. Then copy .kobo to the same drive root, merging folders again.
4. Eject the Kobo safely, disconnect USB and let the update install.

Copy both folders in that order. Leave the .tgz file inside .kobo compressed.

Known issues

• Rotation on Clara devices doesn't work correctly (#5)
• Some books synced via Dropbox or Google Drive won't open (#6)
• Large books may not open on older devices with little RAM (#3)
• Some CJK characters may not display correctly in the chapter list (#2)

Checksums · Build information

Source code and dependencies

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I've also attached a very early Android build.