HP motherboards and BIOS are custom propietary...as you could probably notice there are not many optiions you can modify in BIOS settings ...like you are able in a regular motherboard...
So its not possible to have a custom logo or any modification to it!
Mike
HP Pavilion 590-p0026nq, Core i7-8700, 8GB, 1TB, NVIDIA GeForce GTX 1060+Samsung 970 Evo Plus 256 GB NVMe