We have 2 of them now, see also: Orange pi 4 pro
It is a very new SoC (Allwinner 733) without mainline Linux or U-Boot support yet. Allwinner鈥檚 vendor kernel sources are Linux 5.15 and U-Boot 2018.05 
. At Armbian, someone tried to implement support for some Radxa SBCs with the same SoC (based on these vendor sources), but it was too much custom hassle for them: sun60iw2: add `vendor` kernel support for radxa cubie a7a/a7z by EvilOlaf 路 Pull Request #9145 路 armbian/build 路 GitHub
The sources from Xunolng/Orange Pi:
- GitHub - orangepi-xunlong/linux-orangepi at orange-pi-5.15-sun60iw2
- GitHub - orangepi-xunlong/u-boot-orangepi at v2018.05-sun60iw2
Of course dietpi-installer should work somewhat. Since Xunlong uses an Armbian fork for their image builds, kernel and bootloader are somewhat consistently packaged. But for a proper support our end, it will take a bit longer. Orange Pi 4A is first on my list.
Linking our GitHub issues/requests: