Same issue is occured . HP Bl685c G6 with ESX 3.5 U5 have a unexpected reboot.where the ILO will not be visble and the the remediatin would be resetting the E fuse. . Vmkernel logs shows no clue for any cause and thewhen contacted teh support they say the Firmware would be a prob.
if any insight provided will be great for our issue.
Regards
Karthik