Put sceExts.dll into the NT System32 directory.
Debugger extensions can be accessed by using either one of two methods:
1) Invoke ntsd normally, and refer to the dll name for
each extension call.
ntsd -p <processid for program>
!sceExts.help
!sceExts.DumpSceContext
(2) Invoke ntsd with the following:
ntsd -a sceExts.dll -p<processid>
Then extensions can simply be referenced by name.
!help
!DumpSceContext
NOTE: The argument order is important. I forget which way is correct.
Either the -a or the -p must come first. It doesn't work the
other way around.