TL;DR go to a
root file explorer, Go to /system/media, change
bootanimation_Virgin.zip to .bak, download the boot animation of your choice, rename it bootanimation_Virgin.zip, push it to previous directory, reboot, and voila.
For the longest time, I hated using the stock boot animations on my HP touchpad, so I tried using ROM toolbox to change it. It would always say install complete, but the boot animation would never change. So I looked online, and read the FAQ I believe is where I saw it. You have to change the install location of the boot animation to /data/local if installing to /system/media didn't work. Worked on the HP touchpad, not on our f3. Then I decided to swap around the bootanimation.zip in the/system/media, rebooted, and the boot animation had changed. Please, remember to keep backups of those zips as .oldzip or .bak in case you decide to change it back.
Happy modding