No SD Card Boot Logo payload Customization

[A4EVA]

Hello there, I'm really enjoying this project so first thing first a big thumb up to rehius and all the devs that made this possible. I'm curious to know if the payload array located in payload.h is the actual binary that display the picofly logo on the screen when the sd card is not inserted. If this is the case are the sources of that "boot" payload available ? I would like to add the battery voltage (expressed in millivolt) next to the battery icon if that will be possible. Many Thanks !