A word of caution on using Rom Toolbox for font changes on this phone: I tried to change the font on my phone to Roboto like you mentioned. I navigated to the system/fonts folder and applied the font using the app, but right away my phone rebooted and got stuck in the LG splash screen. There was no way to fix it without using Flashtool to restore it. I don't know why it happened but I'm wary of doing any font changes other than the stock options.