You know that splash screen boot logo that comes up right before your boot animation? Well, that customized logo is simply a bitmap image that is stored in a location where most users will never venture. XDA Elite Recognized Developer jcase located the file responsible, and as it turns out, you don’t even need root access to modify it.
Jcase shared the simple instructions required to backup the default image, “de-customize” the bootloader image, and to flash a new logo. New logos must be in BMP format and be the same size as the original image, which is 720 x 1280.
Please note that to backup the current logo, you do indeed need root access. Flashing a new one, however, is a simple fastboot command that does not require your device to be rooted.
To get started, just head over to the original thread. If you are rooted, you should perform a backup of the boot logo, just in case you ever want it back._________