A wearable medical monitoring device can include a monitor and an update manager. The monitor is configured to monitor a physiological parameter of a subject. The update manager is configured to receive a software update corresponding to the at least one software module for the monitor, and cause an installation of the software update such that the at least one software module installed on the monitor is updated. A wearable medical monitoring device can also include at least one processor, and a supervisory circuit configured to provide redundant booting. The supervisory circuit is configured to monitor a state of the processor when the processor is configured to boot from a current drive. The supervisory circuit is further configured to control the processor to boot from an alternative drive based on the state of the at least one processor or if there is an error caused by the current drive.