If you downgrade from one release to another, you may lose the configuration from your current release. The workaround is to reload the previous controller configuration files saved on the backup server or to reconfigure the controller.
Before upgrading your controller to software release 5.2 in a mesh network, check the boot variable setting before updating the boot. If the boot system image is visible, then no boot variable update is required. If the boot system image is missing, then you must update the boot variable. Refer the below URL for more information on how to check boot variable setting.