I've tried to follow along with your commentary here so that I could mod my N7-2013 Deb boot screen. (It uses the bootloader-deb-flo-04.04.img)
Firstly, even though I haven't been able to follow it to conduct the mod, thanks for the informative write up - I managed to get the gist of it
My Nexus 7-2013 is mounted in the dash of my car, in a reverse landscape orientation.
All I'd like to change for the splash screen is to remove the Google text (just replace it with black) and to turn the padlock 90 degrees (so it's upright when the tablet is in reverse landscape). Fairly simple (I think).
Is there any chance you can do a very quick write up for me on this so I can do the mod?
I just haven't managed to connect the dots between your commentary and what I'm trying to do.
Thanks in advance