I suspect you are powering your Roku via a USB port on the tv which shuts down when you turn off the tv. As a result, the Roku has to boot back up every time you turn on the tv, and if the tv boots faster than the Roku the Roku may not be ready to respond when the tv initially checks the HDMI port to which the Roku is attached.
To recover from this, instead of removing the power from the Roku upon startup, try just switching the tv to a different input and back to the Roku's HDMI port. This will force a new HDMI "handshake" between the Roku and tv.
Perhaps a better solution is to power the Roku via house power using the power adapter that came with it, instead of plugging into the tv's USB port. The Roku will already be booted up when the tv checks the HDMI port and you should be ready to go. If you can't locate the adapter that came with the Roku any adapter you have handy from another device should work, as long as the output information on the adapter's fine print indicates and output of 5 volts and at least 1 amp.
Roku Community Streaming Expert
I am not a Roku employee, only a user like you. Please, no support questions via private message -- post them publicly to the Community where others may benefit as well.
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