You can create your own boot animation for your device. The Android platform provides an easy way to replace its default boot animation by putting a file into /system/media/. 

On the host, use the ADB to download the file into the device.


For example:

$ adb root

$ adb disable-verity

$ adb reboot

$ adb root

$ adb push ~/Downloads/ /mnt/sdcard

$ adb shell


On the device, remount the /system to writable, and copy the file:

# mount -o remount -w /system

# busybox cp /mnt/sdcard/ /system/media/

# mount -o remount -r /system