Remove blue(black) screen, show raw signal (white noise)

Hello, I was wondering if it's possible to remove the black screen that appears when the input signal is too low. I just need a pure, raw signal. Also, how to remove picture auto adjustments, such as auto brightness? I don't have a datasheet for the chip, so I can't recompile the bin file with the necessary commands.

Anyway, thank you very much for this work!