How to change isolinux boot splash

Not plymouth, I mean the actual boot splash that gives you the options of trying out ubuntu, installing ubuntu, checking the disc for defects, etc.

It appears that everything concerning this is in the "isolinux"folder on the ISO. I found some info here: Splash screen before Ubiquity install

But when I follow his commands to create a new bootlogo cpio archive, the boot fails.

I figured out that changing txt.cfg changes the text on the boot menu without needing a new bootlogo, which is great, but I'm having issues changing the .pcx images and gfxboot.cfg. I'd also like to turn off how ubuntu automatically chooses to open the graphical "try or install" window if you don't make a choice in 5 seconds.

Thanks a million to whoever reads this.

Those commands from link you posted actually work. However, you need to do it differently. Here is how I did:

Copy just bootlogo from live CD (or extracted folder) in temporary folder (i will give example in ~/tmp/isolinux/).

Now navigate to the folder and extract bootlogo with command:

cd ~/tmp/isolinux
cpio -i < bootlogo

After this output in terminal must be 1684 blocks (or diferent if it changes).

cat bootlogo | cpio -t > ~/tmp/list

Again, output must be 1684 blocks.

Now edit files and build bootlogo file with:

cpio -o < ~/tmp/list > bootlogo

Again, same amount of blocks must be present (if not changed by you).

And finally, copy other files from /LiveCD/isolinux into your temporary folder (excluding bootlogo ofc.), now you can also copy edited files and overwrite original (or simply skip while copying from LiveCD).

Now it will work.