No boot / blue light

#1

I recently got a Rock 4 C+ but cannot get it to boot.
I’m trying to load Debian and wine for a windows only system.

HDMI cable, monitor, mouse and keyboard, connect power and green light is constant.
I’ve seen other threads say about a switch by the USBs, I don’t this is present on this model.
There is a button next to the SD card slot, holding for 8 seconds appears to shut off the pi.
I’ve tried shorting across 23 and 25 with no change.

I’ve flashed several software types and versions with no success.
I’ve tried 2 alternative SD cards with no change. Fresh 64GB and a 16GB in use.
I’ve tried 2 alternative USB C cables, with various plugs from 1A to 3A. No changes.

I hope i’ve just missed something obvious and easy to fix

#2

What is the image file of the OS you are using?
Please show me the file name of the image.

Typically, the green LED lights up when you turn on the power, and then the blue LED flashes when the OS image is successfully loaded.