I spent a few minutes reading nearby pages. One should start at Page 281, then one should be able to use the selector knob. There are some options that could result in customer calls, such as the Volume Knob Lock and Input Selector Lock.

Inquiring minds want to know what happens if the Input Selector Lock disables the Selector knob, does this completely disable using the knob and the ability to reverse this setting? If so, there must be another, secret reset procedure.

I wonder if you were having some sort of EDID spat and the reboot worked through that.