Hello,I am having problems with my Chinese head unit, while trying to recover from a boot loop I accidentally erased the preloader and now nothing comes up the the screen. I desperately need to identify test points. I tried to find the test points myself without any success. Please help.This is the board version:2020_04_22JAC_8229B2_VER_0.1I also need a tutorial on how to flash this with a new preloader. I found tutorials around but they seem to be for newer boards.