Always feel the fonts in ibooks looks uncomfortable, the following describes a simple tutorial to replace, add fonts.
First, your iPad 2 must be jailbreak, you need upload font to / System / Library / Fonts / Cache / with ifunbox.
Then there is a CGFontCache_H_.plist file in the /System/Library/Fonts/, size 19k, you need to copy it out, opened with pledit.
Add the following codes In
<key>Names</key>
<dict>
Back, such as format:
<key>Names</key>
<dict>
<key>FZLanTingSong</key>
<string>/System/Library/Fonts/Cache/Fzltsk.ttf</string>
<key>FZZhunYuan</key>
<string>/System/Library/Fonts/Cache/FZzhunyuan.ttf</string>
Then add following format:
<key>TraitMappings</key>
<dict>
<dict>
<key>Bold</key>
<string>FZLanTingSong</string>
<key>Plain</key>
<string>FZLanTingSong</string>
</dict>
<key>FZZhunYuan</key>
<dict>
<key>Bold</key>
<string>FZZhunYuan</string>
<key>Plain</key>
<string>FZZhunYuan</string>
</dict>
in
<key>TraitMappings</key>
<dict>
back.
You can add several, but more than five fonts ibooks can not display, when the horizontal screen is the limit of adding five, finally save and replace the original files in iPad 2.