Why the font won't change in certain epubs

[JSWolf]

Originally Posted by Shohreh

Indeed. Turns out simple copying an EPUB and changing its extension from ".epub" to "kepub.epub" disables bookmarking.

If you don't want to edit the file, the right way is to use eg. Kepubify, or Calibre + Kobo Touch Extended plugin

However, EPubMetadataEditor didn't like one of the converted files: "EPUB Metadata Editor Badly formed OPF file.", although bookmarking works.

Even worse with Calibre: Both files trigger this error after converting the EPUB into KEPUB:

************** Exception Text **************
System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at EPubMetadataEditor.Form1.OpenEPUB()
   at EPubMetadataEditor.Form1.Button2_Click(Object sender, EventArgs e)
   at System.Windows.Forms.Control.OnClick(EventArgs e)
   at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
   at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.ButtonBase.WndProc(Message& m)
   at System.Windows.Forms.Button.WndProc(Message& m)
   at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

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Edit: To run it from the CLI

"C:\Program Files\Calibre2\ebook-convert.exe" "input.epub" "output.kepub" --authors "My Author" --title "My Title"

If you are using a current version of calibre, KoboTouchExtended no longer runs. All of it's functionality has been moved to the KoboTouch driver. So now there is only one driver.