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 bootanimation.zip file into /system/media/.
On the host, use the ADB to download the bootanimation.zip file into the device.
For example:
$ adb root
$ adb disable-verity
$ adb reboot
$ adb root
$ adb push ~/Downloads/bootanimation.zip /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/bootanimation.zip /system/media/
# mount -o remount -r /system