It turns out that this is very simple and easy to do. Developer mode needs to be on, of course, and rootfs verification switched off.
The boot animation comprises 17 images, which can be found in PNG format in /usr/share/chromeos-assets/images_200_percent and /usr/share/chromeos-assets/images_100_percent,named boot_splash_frame1.png thru boot_splash_frame17.png.
The boot animation comprises 17 images, which can be found in PNG format in /usr/share/chromeos-assets/images_200_percent and /usr/share/chromeos-assets/images_100_percent,named boot_splash_frame1.png thru boot_splash_frame17.png.
The images can then simply be copied out, edited, and replaced. Extra images can also be added, named boot_splash_frame18.png, boot_splash_frame19.png, and so on, extending the animation. It fades to the desktop after the usual period of time, more-or less, though. I copied frame 17 to frame 18, frame 16 to 19, 15, to 20, and so on, so the animation starts to reverse after it would usually finish.
In addition, the display frame interval can easily be changed in order to speedup or slowdown the animation. Look for --frame-interval in /etc/init/boot-splash.conf (the first instance - the frecon command, is the relevant one on my device).
By default, the frame interval is set to 25.
Change it to 50 or 75 for a slightly slower animation. It is also possible to change the animation background screen colour hex code here as well (although sadly not the initial white boot screen, which is coded into the firmware & requires removal of the write-protect screw to modify).
As an example, here's what I did:
mkdir ~/Downloads/Edited
mkdir ~/Downloads/Backup
cd /usr/share/chromeos-assets/images_100_percent
cp * ~/Downloads/Edited
cp * ~/Downloads/Backup
Opened boot splash files in image editor, made changes. The built-in image viewer in Chrome OS is rather limited so I downloaded the free app 'Image Editor' from the Play Store. Saved edited files to Downloads/Edited. Copied files back to /usr/share/chromeos-assets/images_100_percent
sudo cp ~/Downloads/Edited/boot_splash* /usr/share/chromeos-assets/images_100_percent
vi /etc/init/boot-splash.conf
(changed frame interval from 25 to 50)
vi /etc/init/boot-splash.conf
(changed frame interval from 25 to 50)
sudo reboot
Here's a GIF of what it looks like (if it shows up in a box, that's just due to it being a GIF):
Could be improved, but it's not too bad, for a first attempt, I think.
The edited PNGs forming the above can be downloaded here.
Here's a GIF of what it looks like (if it shows up in a box, that's just due to it being a GIF):
Could be improved, but it's not too bad, for a first attempt, I think.