Ok so something I discovered after wasting many hours - basically Recalbox Dual only works with OS 9 Pulstar if you do an update from a working version of Recalbox 8. If you do a fresh install of currently available Recalbox 9 on a SD card for Raspberry Pi 4 it won’t work with Recalbox Dual. I would advise against purchasing Recalbox Dual until they have fixed Recalbox 9 so that it works with the hardware. Real pity

Hopefully some people have kept image file of Recalbox 8 from which they can upgrade

Ok so basically Recalbox Dual only works with OS 9 Pulstar if you do an update from a working version of Recalbox 8. If you do a fresh install of currently available Recalbox 9 on a SD card it won’t work with Recalbox Dual. I would advise against purchasing Recalbox Dual until they have a version of Recalbox 9 that works with the hardware

By the way, I have the Recalbox Dual with the green PCB board that was purchased in late 2022

Downloaded and installed Recalbox 9 on 64GB SD card and put it in my Pi 4 with Recalbox Dual. When I booted it there was no signal received at all and the TV screen just stayed blue with ‘No Signal’ message. I know the Pi 4 and Hat works fine because I can still run Recalbox 8.1.1 just fine on my CRT tv with same hardware. What’s going on? I thought Recalbox Dual was self configuring and would work automatically with latest Recalbox version. Am I not doing something obvious? Many thanks in advance for any advice