> Does anyone know the details of this "sniffer" program that 
 > OS/2 runs when doing an upgrade?

I don't recall if there were any differences between WARP RED UPG and WARP
BLUE UPG. The most recent (thinking back about 12mths here) problems of
this type were WARP BLUE UPG related. As you probably know WARP BLUE
CONNECT UPG has no sniffer.

It's looking for SYSLEVEL.INI on the install partition, at path
\os2\install (from memory). The file from OS/2 V2.1 is okay, rumour also
had it that the SYSLEVEL.INI file from the UPG itself also allowed install
to continue. Simply creating the partition and placing the path\file there
should allow an installation. I hope you're not wanting to use BootManager,
as it further complicates the problem ;).

Regards.

--- Msgedsq/2 2.2e