[DNSB]

You may want to check the Permanently fix unicode fonts in firmware of Kobo - Including 4.32 thread for some discussion and a link to the font files.

Personally, I would use the extra files option in KoboPatcher to add the font files without needing the unzip and modify used by @mimosavj.

At the end of the kobopatch.yaml files simply add the following lines (replace the <path to font file> with the location of your font files):

<path to font file>\Georgia\georgia.ttf: usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/georgia.ttf
<path to font file>\Georgia\georgiab.ttf: usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/georgiab.ttf
<path to font file>\Georgia\Georgia\georgiai.ttf: usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/georgiai.ttf
<path to font file>\Georgia\georgiaz.ttf: usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/georgiaz.ttf
<path to font file>\Avenir\Avenir.ttf: usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Avenir.ttf
<path to font file>\Avenir\Avenir-Bold.ttf: usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Avenir-Bold.ttf
<path to font file>\Avenir\Avenir-BoldItalic.ttf: usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Avenir-BoldItalic.ttf
<path to font file>\Avenir\Avemir-Italic.ttf: usr/local/Trolltech/QtEmbedded-4.6.2-arm/lib/fonts/Avenir-Italic.ttf