sudo apt-get install netpbm

cd ~/
jpegtopnm logo.jpg >logo.pnm
pnmquant 224 logo.pnm> logo_iunin_clut224.pnm
pnmtoplainpnm logo_iunin_clut224.pnm> logo_linux_clut224.ppm

cp ~/logo_linux_clut224.ppm ~/buildroot/output/build/linux-1ebe8d4a4c96cd6a90805c74233a468854960f67/drivers/video/logo/