first, Get your CUST partition. Open it with WinImage.
then, Go to LGAPP\Media\Font with WinImage. There's a file, "LG_GothicSB_S_V1.00_0902.ttf".This is your actual font
then, to change font:
You must download .ttf font, just rename it to "LG_GothicSB_S_V1.00_0902.ttf" and inject it to your CUST folder LGAPP\Meda\Font using winimage and replace the file and save..then send it back to your phone with km555-utils-en.enjoy your new font ;)
THE FONT MUST BE .TTF!