A system comprising: a plurality of subsystems (106-1, 106-N); a baseboard management controller; and platform firmware, executing on a processing resource separate from the baseboard management controller to implement an automatic diagnostic mode when a boot problem of the system is detected, the automatic diagnostic mode including: iterating through the plurality of subsystems, at each iteration of the iterating, isolating at least one subsystem of the plurality of subsystems in coordination with the baseboard management controller, carrying out a system boot with the at least one subsystem isolated, monitoring the system boot against a watchdog timer of the baseboard management controller, if the system boot completes without the watchdog timer expiring, mark the at least one subsystem that is isolated as a potential cause of the boot problem, and if the watchdog timer expires, continue iterating through the plurality of subsystems; wherein the baseboard management controller is configured to: detect that the automatic diagnostic mode is unresponsive and, in response to detecting that the automatic diagnostic mode is unresponsive, restore the automatic diagnostic mode by isolating, by the baseboard management controller, subsystems that have not been previously isolated by the automatic diagnostic mode. a plurality of subsystems (106-1, 106-N); a baseboard management controller; and platform firmware, executing on a processing resource separate from the baseboard management controller to implement an automatic diagnostic mode when a boot problem of the system is detected, the automatic diagnostic mode including: iterating through the plurality of subsystems, at each iteration of the iterating, isolating at least one subsystem of the plurality of subsystems in coordination with the baseboard management controller, carrying out a system boot with the at least one subsystem isolated, monitoring the system boot against a watchdog timer of the baseboard management controller, if the system boot completes without the watchdog timer expiring, mark the at least one subsystem that is isolated as a potential cause of the boot problem, and if the watchdog timer expires, continue iterating through the plurality of subsystems; iterating through the plurality of subsystems, at each iteration of the iterating, isolating at least one subsystem of the plurality of subsystems in coordination with the baseboard management controller, carrying out a system boot with the at least one subsystem isolated, monitoring the system boot against a watchdog timer of the baseboard management controller, if the system boot completes without the watchdog timer expiring, mark the at least one subsystem that is isolated as a potential cause of the boot problem, and if the watchdog timer expires, continue iterating through the plurality of subsystems; isolating at least one subsystem of the plurality of subsystems in coordination with the baseboard management controller, carrying out a system boot with the at least one subsystem isolated, monitoring the system boot against a watchdog timer of the baseboard management controller, if the system boot completes without the watchdog timer expiring, mark the at least one subsystem that is isolated as a potential cause of the boot problem, and if the watchdog timer expires, continue iterating through the plurality of subsystems; wherein the baseboard management controller is configured to: detect that the automatic diagnostic mode is unresponsive and, in response to detecting that the automatic diagnostic mode is unresponsive, restore the automatic diagnostic mode by isolating, by the baseboard management controller, subsystems that have not been previously isolated by the automatic diagnostic mode. detect that the automatic diagnostic mode is unresponsive and, in response to detecting that the automatic diagnostic mode is unresponsive, restore the automatic diagnostic mode by isolating, by the baseboard management controller, subsystems that have not been previously isolated by the automatic diagnostic mode.