This is only a test of keep u-boot logo util yocto system screen on for some request validation. HW : 8mn-ddr4-evk. SW: 8mn 4.14.98ga-2.2.0 release. 1. patch 2 u-boot patchs. 2. patch kernel patch. 3. changed kernel config to remove CONFIG_FRAMEBUFFER_CONSOLE and CONFIG_LOGO.