The following sequence of commands can cause a system
2. swtrace init -s 50
3. swtrace on
4. swtrace enable 4 17 25 49 50
5. swtrace it_install -ss
If you insert 'swtrace off' and 'swtrace it_remove'
between steps 5 and 6, the pi_unload completes
successfully. I will attach a patch to this bug that
changes the pi_unload.sh script to do a complete
teardown in case the user has not done so.