Libra Colour in invert (not dark) mode flashes to white every page turn

[RobertJSawyer]

I'm visually impaired and need a black background everywhere — and so I use "Invert Mode" (as distinct from the standard "Dark Mode" available through the stock user interface). "Invert Mode" is available through NickelMenu and inverts everything (book, dictionary, user menus, home screen — everything):

menu_item :main :Invert & Reboot :nickel_setting :toggle :invert

On my old Libra 2, that worked just fine: everything (the book, dictionary, and all other UI elements) had a black background, which only switched to white during a page refresh (which I had set to every chapter).

But I've just bought a Libra Colour, and in "Invert Mode," regardless of what setting I have for "refresh pages," the background flashes to white for each page change.

NOTE: If I use standard "Dark Mode," instead of "Invert Mode," this does NOT happen -- but then the dictionary and UI elements all have white backgrounds, making the Libra Colour useless for me.

Any suggestions, other than returning the Libra Colour?

[PeterT]

I wonder if it might be related to the issue mentioned near the end of the NickelClock thread?

[RobertJSawyer]

Hi, Peter. I tried installing NickelClock 0.4.0 (the latest), which is supposed to fix a specific screen-flashing problem on the Libra Colour after highlighting a passage, but it makes no difference to my overall problem of the screen going white after every page turn.

It's really disappointing, as otherwise the Libra Colour is a lovely device.

[PeterT]

No. I don't think NickelClock would solve the issue; it's just that the author mentions an issue in the Kobo firmware that caused a most annoying flicker with NickelClock and I was wondering if that underlying issue is the one causing the darkmode problems

[RobertJSawyer]

A few observations I've made during additional testing:

The flashing to white every page turn happens regardless of which renderer you're using: it happens for both .kepub and plain sideloaded .epub files.

BUT it is not a necessity brought about by the colour layer. If you press and hold on the lower right corner of the screen when a book is open, the Libra Colour does high-speed paging forward with NO bounce to a white screen between pages (and if you press and hold the lower left, no bounce occurs as it pages backward).

NOR is this required when updating screens with colour on them. For instance, there's no bounce to white when paging through "My Books" (or any other multipage menu).

[RobertJSawyer]

(And, of course, this is NOT a NickelMenu issue; if you have DevModeOn, you can toggle "Invert screen" there — Nickel Menu is just a handy way to do that more quickly.)

[Aleron Ives]

I don't know if this would help, but you could try editing Kobo eReader.conf on your computer and changing numPartialUpdatePageTurns to a high number like 50, then save the file, eject your Libra, and reboot it. This might be enough to force the screen refreshes to go away, but it's possible this is just a bug with inverted mode, since you're not supposed to be using it.

[RobertJSawyer]

Originally Posted by Aleron Ives

I don't know if this would help, but you could try editing Kobo eReader.conf on your computer and changing numPartialUpdatePageTurns to a high number like 50, then save the file, eject your Libra, and reboot it. This might be enough to force the screen refreshes to go away, but it's possible this is just a bug with inverted mode, since you're not supposed to be using it.

Before I modified it, the value for numPartialUpdatePageTurns was already set to 4294967295, which is obviously a lot higher than 50. Still, I tried what you suggested, and it didn't help. But thank you!

[John F]

Maybe try installing an earlier firmware version?

[PeterT]

Originally Posted by John F

Maybe try installing an earlier firmware version?

The EARLIEST release for any device is what it was released with. Installing an older version than that would just brick the device

[John F]

Originally Posted by PeterT

The EARLIEST release for any device is what it was released with. Installing an older version than that would just brick the device

Oxymoron: how can you install a version before the earliest?

Is Robert on the earliest version? Has Robert seen if the problem still persists after doing the factory reset (assuming that goes back to the earliest version) he mentioned in the other thread?

[DNSB]

Originally Posted by John F

Oxymoron: how can you install a version before the earliest?

I've seen several issues where people have caused themselves issue by installing a firmware revision older than the factory version. Kobo has improved this in their newer firmware but you can still take advantage of their open system to screw things up totally.

But I wanted my Clara BW to have the UI from v3.19 for instance.

[RobertJSawyer]

I did a normal factory reset, and the problem with a white flash after every page in INVERT mode persists — and I was left on the updated firmware 4.45.23697.

I then did a hard factory reset (hold down a page-turn button, then power on), and the Firmware reverted to the as-shipped version, 4.42.23296, and the problem still persists.

[PeterT]

I'm not surprised at all. As I mentioned in your other thread this sounds identical to the issue that caused NickelClock to flash the screen and required a work around in its code to solve the issue.

I did post that info to some Kobo developers but (as you've noticed) it seemed to fall on deaf ears.

[Waldy]

Originally Posted by RobertJSawyer

I did a normal factory reset, and the problem with a white flash after every page in INVERT mode persists — and I was left on the updated firmware 4.45.23697.

I then did a hard factory reset (hold down a page-turn button, then power on), and the Firmware reverted to the as-shipped version, 4.42.23296, and the problem still persists.

I got a positive result with firmware version 4.39.22443; that’s the version I have after a hard reset. With firmware 4.39.22801 the screen flashes white. I’m not sure if it’s possible to find 4.39.22443, but if not, I can share my `recovery.img` for the Libra Colour if needed.