But if you made the install using a fat PS2 and did not have a DVDPLx from a slim PS2 stored as "DVDELF.BIN" in the "INSTALL\INJECT\" folder of the installation package, then the installer had no choice but to use the DVDELF KELF file from the bios ROM, and that one has a size somewhere between 1.3 and 1.5 MB (not sure of the limits).
The DVDPLx KELFs from a a slim PS2 are all quite small though. Mine are 75136 bytes, and that is what will be used to replace the big one mentioned above, so whatever the size difference between them is, that is the space you would save on your own MC.
Multi-Install simply means that you are ensured that your MC will boot on all consoles of the same region as your own (barring the latest model with bios v2.30). So you can bring your MC to the consoles of any friends and use your MC to boot there, as long as the console is of the same region as yours, and regardless of what model it is (before bios v2.30).That's a very good step considering that I had to clean about 3.2MB just to make the noobie install, and I didn't use the Multi-Install option... because It didn't sound the right one.
The 'standard' install might work on some other models but there would also be many it couldn't work with.
I've always felt so, but I am admittedly biased as I use it so much.And yes, it seems a good ideia to keep the BOOT.ELF ulaunchelf on the mc.
Best regards: dlanor