I've recently started encountering an issue whereby then I reboot the Icon 600 attached directly to a Sharp PN-U423, the initial boot/load screen appears, then goes blank, then never fails to re-display content to the TV.
The Lifesize boots completely, to resolve this issue I have to power cycle the TV.
I've tested the Icon 600 on the 60" revision of the same TV - this works fine.
I've tested different Icon 600s and different Sharp PN-U423 - same symptoms.
If I use an FSR touch-panel and Gefen HDMI switcher - this works fine (I no longer wish to use these devices). But a direct HDMI connection between Icon 600 and Sharp PN-U423 does not. The signal is lost somewhere. All sleep settings are disabled on the TV. TV does not exhibit this behaviour with any other device.
TV has had no available firmware updates.