Solid Red + Green LED

Installation
1

Hi

Received my HA Yellow with CM4 + SSD
Connected to network + Plugged in - Constant Red + Green LED’s
Assumed device software is not on board as expected so connected to PC & reloaded via USB-C then reinstalled firmware using USB drive which progressed all the way to solid Red LED indicating success.

Ethernet cable plugged in - insert power cable (Non POE unit) - Solid RED + Green LED’s!?
Tested Ethernet cable - can access internet using cable with Wifi disabled.

Any Ideas?

2

Update:
Reinstalled using RPIBOOT
Flashed os
Still not working…
Connected putty serial debugger, black screen pops up but pressing enter does not progress to next step.

Any ideas?