We installed three Group 500 systems eight months ago and all were running fine. They are integrated into a Crestron controlled A/V system. Crestron is using a combination of RS232 and IR to control the Group 500s. The end user updated firmware to 4.1.3-111080 to allow desired web based interface changes. All three Group 500 systems are now experiencing intermittent lockups. When locked up, Crestron cannot control them via rs232 or IR. The Factory remote will also not work and the WEB interface cannot link to the unit. A power cycle of the Group 500 will restore full operation until the next lockup which may be days or weeks. Any words of wisdom?