I understand. Don't worry.
Originally Posted by joseri
In replacement of the multi-installation mode, the normal installation mode now has three sub-options: Normal installation, cross-model, and cross-regional:
Normal installation: The FMCB installation will work only on this console (and consoles around the same model, but within the same region as the one FMCB is installed for).
Cross-model: The FMCB installation will work with all models (Except for the SCPH-90000 and PX-300 series with boot ROM v2.30 and above) of PlayStation 2 consoles within the same region of the console which FMCB is installed for.
Cross-regional: It works the same as the multi-installation option, but it installs files for all console models in all regions (read below for more information).
As for why the multi-installation isn't recommended: The memory card does not support soft-linking, which means that files cannot have "aliases" (multiple names). Consoles of different series and regions will look for files named differently. The multi-installation will cross-link (introduces controlled filesystem corruption) files to satisfy that requirement, but it's not exactly a good thing because it's still corruption and is a hack (It goes against the design of the memory card).
Also, the multi-installation has a (really old by today) bug that causes corruption, depending on the content of the card. By right, it should be fixed... but I can't do that because it's a very complicated matter and I don't even know where to start.
I left the multi-installation option there only because I know that there will be people who will complain that the cross-regional option takes up too much space.
SCPH-10000 S. MINOKAMO v1.01 (Defunct)
SCPH-10000 S. KISARAZU v1.00 (faulty)
SCPH-15000 S. KOHDA (With warranty seal!) :D
DESR-5100 S. EMCS