The SLX-OS software (firmware) download is performed incrementally, unless otherwise specified. The firmware download command compares the new software packages against the current installation and only downloads the packages that contain new features or have been modified.
If a software download session is interrupted by an unexpected reboot, SLX-OS attempts to recover the previously installed software. Success depends on the state of the software download. You must wait for the recovery to complete before starting another software download.