There are four on-board LEDs that indicate the following:
Green power (Pwr)
Displays when the board is powered up and not in reset mode. Flashes during the firmware update process.
Green file-system activity (Bsy)
Flashes any time there is file-system activity (on any storage device)
Blue WiFi ()
Flashes when the player is connecting to the wireless network. Displays when connected.
Red status (Err)
Flashes a certain number of times to indicate which error is occurring. The flash codes are described below.
Network recovery script is preparing to run on a device configured for network recovery.
No upgrade file found.
Failed to load kernel module.
Board is not capable of running the current firmware version.
A piece of on-board hardware is not working correctly.
Problem related to the storage device (either the USB drive or microSD card)
Problem related to the registry/NAND
The autorun script encountered a load/run error.
Unable to find a bootable image.
The on-board switch is connected to the GPIO12, which is pulled low when the service (SVC) button is pressed. Conversely, a pull-up on the button normally sets the GPIO12 to be pulled high.
The XT243 and XT1143 have an internal M-keyed M.2 slot for ATAPI SSD drives. See this page for all SSD specifications.