Boot logos, or better to call them "splash logos" need to be flashed, can't be "installed". They must have exactly the size and the RGB scheme and they are originally bmp files.
A valid bootlogo has got a 1Mb size, 720x476 pixels, RGB8 color scheme, depth 8 and 72 dpi.
Then you need to rename it as
splash_auto.bin
and put into a flashdrive with the usual structure for the flash.
For instance, if your box is a Solo4K, it must be within the folder
/vuplus/solo4k
Viceversa, if you flashed your preferred splash logo and afterwards you want to flash your box with a new image, check that there is no splash_auto.bin file along with the others and, in case, delete it before flashing.