Replacing Kindle's built-in fonts

[t123yh]

You can replace any built-in font (for example, replace the Amazon Ember)!
This tutorial is for Linux users. Windows users may do this using some other squashfs tools, but unfortunately I don't have a Windows device at the moment)

You should have some basic knowledge of Linux such as mount, symbolic link and such. I'm not responsible for any damage on your device!

I replaced the Chinese Heiti to Source Sans Hans without any problem. Tested on my PW3.

Here's what I do:
1. Jailbreak
2. Install USBNetwork hack and enable it on boot (Important!)
3. Transfer the fonts file to your Linux computer (this should be done on your computer):

scp root@192.168.15.244:/usr/java/lib/fonts.sqsh .

4. Unpack the fonts file using unsqushfs:

unsquashfs fonts.sqsh

Now you should see a squashfs-root directory. All the fonts should be in it.
5. Replace the fonts you want. Note that otf can be directly renamed to ttf and will work.
6. Do some stuff on your kindle:

stop x
cd /usr/java/lib
umount fonts
mv fonts.sqsh /mnt/us # make a backup in case things do not work.

7. Copy fonts to your kindle (on your computer)

scp -r squashfs-root/* root@192.168.15.244:/usr/java/lib/fonts

8. Reboot your kindle.

reboot

And enjoy. If Kindle keeps rebooting, ssh into your kindle and do:

stop x
rm  /usr/java/lib/fonts/*
cp /mnt/us/fonts.sqsh /usr/java/lib
reboot

Note that system upgrades may completely wash this out and even make your device a brick. I'm not responsible for anything; But keep your USBNetwork on at boot to prepare for any incidents!

[knc1]

And to avoid the documented problems with USBnetwork "auto" mode -
Instead use the combination of RP and CRP.