Hello!
For your NXP Matter thermostat issue, the most likely cause for it not running after a reset (despite working in debug) is that your application isn't correctly flashed for standalone boot or there's a specific bootloader configuration needed for the RT1060-EVKC and Maya-W276 (IW612). You'll need to check NXP's documentation for "production flashing" or "boot from flash" instructions. Regarding adding/removing custom Matter clusters, the primary tool is ZAP (ZCL Advanced Platform). You'll define your cluster in an XML file, integrate it with ZAP to generate C++ code, and then implement the specific application logic. Look for NXP's Matter SDK documentation, their GitHub repository, or the general Matter (CHIP) SDK guides on "Manufacturer Extensions" or "Custom Data Models" for detailed steps.