How to change system font

Hi~I'm Panda_Kim in Korea~

I solved Problem yesterday , by Master's help!

Today's question is "How to change system font"

Font location is ~share/fonts/truetype/droid/DroidSansFallbackFull.ttf

But after reboot , font is restored.

Help me ~

I do it, but after reboot, font file is restored.

if the file is restored, you didn't save the overlay.