Secondary Secure Bootloader

Hi,

The present bootloader on Pixhawk Cube is not secure. Is there any way I can load secondary bootloader like U-Boot to verify integrity of Px4 firmware? The present bootloader is present at 0x08000000 flash memory address and firmware is at 0x08004000. I want to add another bootloader to this configuration to ensure the software integrity. Is there any similar work going on? How should I begin with this?

Vishal