The last regular firmware version of the FiiO X3II digital audio player is 2.0 at FiiO's site. An interesting previous version is 1.4, the last with OTG support (adding storage on the USB port, which is not officially supported but works for most).
FiiO allows the firmwares to be customised with alternative images and graphical properties (colours, font sizes...). FiiO shares instructions on how to customise a firmware, how to install a firmware, and its own large text font firmware. Here are some public firmware variations shared on Head-Fi:

Off the shelf firmwares

Arielp's big font
See post
See post 
Zweistein's high-contrast, bold font
Shared on dropbox, source files and scripts on github. All themes have larger playtime and track numbers (below the progress bar) and reveal as much as possible of the album art with little transparency so text stays readable.The themes are:
  • White/green on black
  • Same as 1 but with the traditional line as progress bar
  • White/orange in slightly bigger font, with watery progress bar
  • Same as 3 but with pacman progress bar
  • Same as 1 but with a big font - the biggest that still shows all letters completely
  • Same as 1 but with an even bigger font - cutting off the tail of lowercase letters g, j, p, q, y.

DIY corner

Some tips if you want to create your own customization.


Superfluous files
In 2.0, these folders and files are not used at all and can be removed:
  1. litegui/test
  2. litegui/theme?/list/headset.png
  3. litegui/theme?/list/lineout.png
  4. litegui/theme?/m3u/long_menu_bg.png
  1. litegui/theme?/msg/bg_base.png
  2. litegui/theme?/msg/dock_insert.png
  3. litegui/theme?/msg/dock_remove.png
  4. litegui/theme?/msg/full.png
  5. litegui/theme?/msg/lock.png
  6. litegui/theme?/msg/none.png
  7. litegui/theme?/number/L.png
  8. litegui/theme?/number/R.png
  9. litegui/theme?/topbar/shade.png