This is how I installed the service pack on an OS/2 2.0 italian version.
I cannot offer guarantees of any kind about the results on other systems, but my system is working apparently OK, with SVGA 256 colors, and all the rest.
When I tried first to install (I made a backup of my HPFS just before) the
SERVICE command told me he didn't see packages to upgrade.
The problem is in the package's name, which is, for Italy, XRI0000 instead
of XR00000.
I changed twice the package's name in C:\OS2\INSTALL\SYSLEVEL.OS2.
The SYSLEVEL.GRE file is OK.
Then i run the servpak install, and now it seems quite good.
On my system it looks faster, although now I'm running 256 colors.
Only, now I'm driving fool switching continuously my answers from si/no to