Custom BlackView BV4800
Lets modify file in ROM
Installa Magiskboot
https://aur.archlinux.org/packages/magiskboot-bin
yay -S magiskboot-bin
Change picture on boot
download file from rom like boot.bin , vbmeta.bin , super.bin
use command to unpack file
magiskboot unpack magisk_patched-26100_biB8t.img
use command to repack file
magiskboot repack magisk_patched-26100_biB8t.img