Sparc T5240 ILOM password grief
To reset using the jumper. You must remove all power/unplug. Move the jumper. Plug back in and wait 30 seconds or so...possibly longer on these beasts. press and hold the power button (10 seconds usually works), it will not power up. Release the power button, unplug, reset jumper. Plug back in and the Ilom pass should be reset. Default user/pass is root/changeme.
Hope this helps