Kobalt: an alternative reader app for Kobo devices - Page 2

fogice · 10-11-2026, 10:30 AM

Super interested in this.

I assume all the other mods of yours (NickelDissolve, NickelTypeFix) only function in the built-in reader, so they would co-exist with Kobalt and I don't need to uninstall them?

Should I install both Libron (for Kobalt) and KF Libron (for Nickel)?

The video discusses the tap zones for page forward and page backward. Are there alternative tap zone layouts (I presently use page forward on bottom, page back on top)? Do you have the ability to create custom tap zones (my dream layout is all single taps are page forward, all other actions are long-presses or swipes)?

You say that the initial book open takes longer. If I switch to Book 2 and back to Book 1, does it have to recalculate? And how does it handle very big books (over 10,000 pages)? Does a font size change also have to recalculate the entire book?

rantanplan · 10-11-2026, 10:54 AM

I've been using Kobalt this whole afternoon and it works well so far. I really love it.

Is there a way to set the current layout and font-size as default?

MrSilverstrike · 10-11-2026, 11:18 AM

Quote:

Originally Posted by fogice

Super interested in this.

I assume all the other mods of yours (NickelDissolve, NickelTypeFix) only function in the built-in reader, so they would co-exist with Kobalt and I don't need to uninstall them?

Should I install both Libron (for Kobalt) and KF Libron (for Nickel)?

The video discusses the tap zones for page forward and page backward. Are there alternative tap zone layouts (I presently use page forward on bottom, page back on top)? Do you have the ability to create custom tap zones (my dream layout is all single taps are page forward, all other actions are long-presses or swipes)?

You say that the initial book open takes longer. If I switch to Book 2 and back to Book 1, does it have to recalculate? And how does it handle very big books (over 10,000 pages)? Does a font size change also have to recalculate the entire book?

Ho, lots of questions.

1. All other mods keep working and benefit the built-in reader in case you have purchased books.

2. You should not install Libron. It comes with Kobalt. KF Libron is for the built-in reader if you still want to use that, so keep it installed.

3. Tap zone customization is coming in a later update. Not sure how it'll work yet, probably the same presets as Kobo offers + "tap anywhere to go to the next page". Currently, all other actions are long presses (for links and dictionary lookup).

4. Initial loads take longer. However, there's caching, so it's only the first load that's really significantly longer. Subsequent loads should be faster, although if you install an update for Kobalt the cache is rebuilt. Switching between two recently opened books should be relatively quick.

5. A font change recalculates the pages in the book, so it may take a while, but only after you've confirmed it. You can make edits as a preview to the current page without needing to wait every time. When you return to the book and dismiss the font/layout panel, the entire book layout pass happens.

MrSilverstrike · 10-11-2026, 11:19 AM

Quote:

Originally Posted by rantanplan

I've been using Kobalt this whole afternoon and it works well so far. I really love it.

Is there a way to set the current layout and font-size as default?

Not yet! I did mention this in the video. Presets and defaults are coming later.

JSWolf · 10-11-2026, 11:31 AM

Quote:

Originally Posted by rantanplan

Is it possible to enlarge an illustration? In Nickel it’s doublepress, in KOReader it’s longpress but both don’t seem to do the job with Kobalt.

That's not in Nickel. The image enlargement is in the renderer for KePub.

Gormagon · 10-11-2026, 11:42 AM

Quote:

Originally Posted by MrSilverstrike

I just uploaded an early Android debug build.

That was really fast!

For testing I installed it on my new 4" mini phone Oukitel C17 Mini, which is just Android Go 16 with a LCD screen.
At first the volume buttons weren't working for page turning. Then I disabled the app VolumeScroll and the buttons are working as expected. Strange, in KOReader or Librera there aren't any problems with VolumeScroll and page turning.

I see that I can't use my dictionaries I already installed for KOReader. I just could download some other dictionaries. The rather old GoldenDict app, which I use for Librera, has the option to use installed dictionaries from other apps.

Right now with a restart of Kobalt I just see the last books I've opened but no option that Kobalt enters the last read book directly after a restart.

Kobalt closes itself when I tried to open 2 epub books fron SpringerNature (27 MB and 41 MB). KOReader has no problems with these files.

2 novels (5 MB and 15 MB) I could open w/o problems. For the first I set "Jost" as default font. But when I opened the other novel the text was in Libron, not Jost.
Also the layout isn't the same I selected for the first novel.
I haven't found an option to select my own favourite fonts.

The progress bar is at the bottom, I like all the stuff in the top bar and nothing at the bottom. Having an option to select only top, only bottom or like it is now would be nice.

Kobalt starts faster then KOReader but since it's only starting in a minimal mode with the last book and "Choose books" as well as "Exit Kobalt" that should be expected.

Since the filenames of my books are somethimes a mess (like 978-3-032-22637-2.epub, one of the aforementioned SpringerNature books), I'm not really a fan of having only a filename list to choose from. But then, Kobalt is more about simplicity, I guess. And the apk just a first version.

MrSilverstrike · 10-11-2026, 12:00 PM

Quote:

Originally Posted by Gormagon

That was really fast!

For testing I installed it on my new 4" mini phone Oukitel C17 Mini, which is just Android Go 16 with a LCD screen.
At first the volume buttons weren't working for page turning. Then I disabled the app VolumeScroll and the buttons are working as expected. Strange, in KOReader or Librera there aren't any problems with VolumeScroll and page turning.

I see that I can't use my dictionaries I already installed for KOReader. I just could download some other dictionaries. The rather old GoldenDict app, which I use for Librera, has the option to use installed dictionaries from other apps.

Right now with a restart of Kobalt I just see the last books I've opened but no option that Kobalt enters the last read book directly after a restart.

Kobalt closes itself when I tried to open 2 epub books fron SpringerNature (27 MB and 41 MB). KOReader has no problems with these files.

2 novels (5 MB and 15 MB) I could open w/o problems. For the first I set "Jost" as default font. But when I opened the other novel the text was in Libron, not Jost.
Also the layout isn't the same I selected for the first novel.
I haven't found an option to select my own favourite fonts.

The progress bar is at the bottom, I like all the stuff in the top bar and nothing at the bottom. Having an option to select only top, only bottom or like it is now would be nice.

Kobalt starts faster then KOReader but since it's only starting in a minimal mode with the last book and "Choose books" as well as "Exit Kobalt" that should be expected.

Since the filenames of my books are somethimes a mess (like 978-3-032-22637-2.epub, one of the aforementioned SpringerNature books), I'm not really a fan of having only a filename list to choose from. But then, Kobalt is more about simplicity, I guess. And the apk just a first version.

Yes, this is still very much an early build, and some of the book loading bugs are being reported on GitHub now. Lots of fixes rolling in as we speak.

This is like a sneak preview, please stay tuned for a proper release later

(Thank you for the feedback so far!)

Strether · 10-11-2026, 02:07 PM

I installed this on my Libra 2, and had no trouble doing that. But the only book that it will open is the last book I was reading before I installed it. All the other sideloaded DRM-free books wouldn't open in Kobalt, though they open without problems in the original OS.

Jim

MrSilverstrike · 10-11-2026, 02:09 PM

Quote:

Originally Posted by Strether

I installed this on my Libra 2, and had no trouble doing that. But the only book that it will open is the last book I was reading before I installed it. All the other sideloaded DRM-free books wouldn't open in Kobalt, though they open without problems in the original OS.

Jim

Hi Jim, I've had folks report the same issue. Should be fixed in beta 2, which should be live in half an hour or so. (You'd have to go through the wizard on the website to upgrade.)

Edit: Live now!

Strether · 10-11-2026, 02:36 PM

Thanks, I'll do that when it's available. I did reboot the Libra and that helped opening most of the books, though it doesn't open the book directly. Instead you get a menu with the option to open the book, then it opens.

Not crazy that the settings for thickness and size of the font don't remain from book to book, and also, on all books, the chapters are all grayed out. I don't see any way to return to a previous chapter, or the start of the book.

I do like seeing the clock and the amount left on the battery.

Jim

MrSilverstrike · 10-11-2026, 02:43 PM

Quote:

Originally Posted by Strether

Thanks, I'll do that when it's available. I did reboot the Libra and that helped opening most of the books, though it doesn't open the book directly. Instead you get a menu with the option to open the book, then it opens.

Not crazy that the settings for thickness and size of the font don't remain from book to book, and also, on all books, the chapters are all grayed out. I don't see any way to return to a previous chapter, or the start of the book.

I do like seeing the clock and the amount left on the battery.

Jim

Most of these things with the exception of the font settings are bugs, and should also be fixed in beta 2!

Strether · 10-11-2026, 02:52 PM

The new update fixed the problem, in that all the books I tried to open, do open. Some open directly and others present me with the menu I mentioned previously. Also, the chapters are no longer grayed out, so you can go back to the beginning of your book, or any other chapter you want.

I do appreciate all your work on this.

Jim

Sirtel · 10-11-2026, 03:08 PM

Do the page turn buttons work? And can you set the full refresh every page?

MrSilverstrike · 10-11-2026, 03:24 PM

Quote:

Originally Posted by Sirtel

Do the page turn buttons work? And can you set the full refresh every page?

Yes and yes!

dhampny · 10-11-2026, 04:25 PM

Just installed Kobalt on my Libra Color. Very easy to install and your introduction is a great aid to getting up and running. Very impressive! Thanks for this.

I see in your Walkthrough that you have the book title in the header. I'm only able to see the chapter title. How can I change that?

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10-11-2026, 10:30 AM	#16
fogice Addict Posts: 354 Karma: 50000 Join Date: May 2014 Device: Kobo Libra 2 & Clara BW	Super interested in this. I assume all the other mods of yours (NickelDissolve, NickelTypeFix) only function in the built-in reader, so they would co-exist with Kobalt and I don't need to uninstall them? Should I install both Libron (for Kobalt) and KF Libron (for Nickel)? The video discusses the tap zones for page forward and page backward. Are there alternative tap zone layouts (I presently use page forward on bottom, page back on top)? Do you have the ability to create custom tap zones (my dream layout is all single taps are page forward, all other actions are long-presses or swipes)? You say that the initial book open takes longer. If I switch to Book 2 and back to Book 1, does it have to recalculate? And how does it handle very big books (over 10,000 pages)? Does a font size change also have to recalculate the entire book?

10-11-2026, 10:54 AM	#17
rantanplan Weirdo Posts: 1,351 Karma: 13516840 Join Date: Nov 2019 Location: Wuppertal, Germany Device: Kobo Libra 2, Tolino Vision Color, reMarkable PaperPro	I've been using Kobalt this whole afternoon and it works well so far. I really love it. Is there a way to set the current layout and font-size as default?

10-11-2026, 02:07 PM	#23
Strether Guru Posts: 773 Karma: 2825929 Join Date: Feb 2007 Location: Fresno Device: Kindle 1; iPad Air; iPhone 7; Kobo Libra; Kindle Oasis 3	I installed this on my Libra 2, and had no trouble doing that. But the only book that it will open is the last book I was reading before I installed it. All the other sideloaded DRM-free books wouldn't open in Kobalt, though they open without problems in the original OS. Jim

10-11-2026, 02:36 PM	#25
Strether Guru Posts: 773 Karma: 2825929 Join Date: Feb 2007 Location: Fresno Device: Kindle 1; iPad Air; iPhone 7; Kobo Libra; Kindle Oasis 3	Thanks, I'll do that when it's available. I did reboot the Libra and that helped opening most of the books, though it doesn't open the book directly. Instead you get a menu with the option to open the book, then it opens. Not crazy that the settings for thickness and size of the font don't remain from book to book, and also, on all books, the chapters are all grayed out. I don't see any way to return to a previous chapter, or the start of the book. I do like seeing the clock and the amount left on the battery. Jim

10-11-2026, 02:52 PM	#27
Strether Guru Posts: 773 Karma: 2825929 Join Date: Feb 2007 Location: Fresno Device: Kindle 1; iPad Air; iPhone 7; Kobo Libra; Kindle Oasis 3	The new update fixed the problem, in that all the books I tried to open, do open. Some open directly and others present me with the menu I mentioned previously. Also, the chapters are no longer grayed out, so you can go back to the beginning of your book, or any other chapter you want. I do appreciate all your work on this. Jim

10-11-2026, 03:08 PM	#28
Sirtel Grand Sorcerer Posts: 15,836 Karma: 251102463 Join Date: Jan 2014 Location: Estonia Device: Kobo Sage & Libra 2	Do the page turn buttons work? And can you set the full refresh every page?

10-11-2026, 04:25 PM	#30
dhampny Enthusiast Posts: 30 Karma: 24 Join Date: Feb 2009 Location: Rochester, NY Device: Libra 2, Color Libra, Inkpad 4, Verse Pro	Just installed Kobalt on my Libra Color. Very easy to install and your introduction is a great aid to getting up and running. Very impressive! Thanks for this. I see in your Walkthrough that you have the book title in the header. I'm only able to see the chapter title. How can I change that?

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