@davem, I have similar X88 Pro TV box clone which got "X88PRO-RK3566-4D32-V2.1" written on the PCB. I was struggling to boot the system using SD card since the Android image that came with the box was not allowing.
Thanks for sharing about the upgrade tool and modified x96x6.dtb. Without your posts I could not made it to work. I got "Armbian_community_26.2.0-trunk.792_Rk3566-box-demo_trixie_current_6.18.24_minimal.img.xz" successfully writte and booted. Later I have installed KDE based Desktop as well on 64GB Micro SD card. My USB 3.0 (the blue one) is somehow not working, Since I have a USB hub its not a deal breaker. Following are working properly as of now.
Summary:
Bluetooth - Working
On Board LAN - 1000Mbps - Working.
WiFI - connected to 2.4 Ghz network - Working.
HDMI Display - Working. I have not test HDMI audio though.
Sound - No 3.5mm Analog jack in this model. However the sound is working via Bluetooth head phone and Speaker with USB input/power.
USB 2.0 - Connected Keyboard, mouse and speaker via USB 2.0 Hub - Working.
USB 3.0 - This works fine when we boot in Android - Not working.
Toss Link - Though the box got a port in the back, I don't have any device that can be connected - Not Tested.
Note: I have windows 11 system as my desktop PC. I could not edit the Micro SD card created using BalenaEtcher. I had to use Ubuntu system in order to prepare the SD card and to edit the boot/armbianEnv.txt with fdtfile=rockchip/rk3566-box-X88PRO20.dtb