Tweaking a U8G2 font?

Is there a tool that can import a U8G2 font and allow me to adjust it (all I need to do is flip some of the pixels to change the shape of one of the characters). I dont have the source of the original font.

Regards,
Dave

Try this glyph editor:
https://dagnall53.github.io/Fonts-for-WiRocs/glyphEditor2.html

It takes the data bytes from the font .h file.