Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32f4/STM32F429/LTDC/L1CLUTWR#0x0
Layerx CLUT Write Register
Blue value
Green value
Red value
CLUT Address
https://github.com/modm-io/cmsis-svd-stm32