http://askiiart.vernccvbvyi5qhfzyqengccj7lkove6bjot2xhh5kajhwvidqafczrad.onion/blog/marlin-boot-animations.html
For a static boot screen, only use custom_start_bmp . Each array looks like the one below, which is the Linux Mint
logo. const unsigned char custom_start_bmp [] PROGMEM = { B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 , B11111111 ,...