My new A7R II switched on OK. I initialised the SD card, then turned it off, to make sure I had lens and rear screen protectors installed before using it.

On trying to start again - nothing. Except that the red "Access LED" at the back flashes regularly, a series of 11 flashes, then a pause, then repeat. Pulling the battery and/or the SD card doesn't make it recover.

I'm sure this is a BIOS error code, or equivalent, but I can't find any literature that says what it means. Does anyone know?