HOWTO Use custom font on Kobo

To use a custom font for word definitions, you need to use a custom firmware.

Pre-requisite

• Connect the Kobo to the computer.
• In my case, I defined those envars to point to the folder where the device is mounted:

  export KOBO_ROOT="/media/$USER/KOBOeReader"
  export KOBO_DIR="${KOBO_ROOT}/.kobo"

The Font

First, download and copy the font (FreeSerif:

$ wget "http://ftp.gnu.org/gnu/freefont/freefont-ttf-20120503.zip" \
    && unzip "freefont-ttf-20120503.zip" \
    && cd "freefont-20120503" \
    && mv -v "FreeSerif.ttf" "FreeSerif-Regular.ttf" \
    && mv -v "FreeSerifBold.ttf" "FreeSerif-Bold.ttf" \
    && mv -v "FreeSerifBoldItalic.ttf" "FreeSerif-BoldItalic.ttf" \
    && mv -v "FreeSerifItalic.ttf" "FreeSerif-Italic.ttf" \
    && mkdir -pv "${KOBO_ROOT}/fonts" \
    && cp -v FreeSerif*.ttf "${KOBO_ROOT}/fonts"

The Firmware

In the kobopatch, find the "Dictionary text font-family/font-size/line-height" section and add this line:

  - ReplaceString: {Offset: 54, Find: "Georgia  ", Replace: "FreeSerif", MustMatchLength: yes}

(comment all previous lines)

Save, patch, and you are good to go.