Images for non LTS version can be downloaded here
Legacy kernel based images are using improved and updated stock kernel with proprietary boot loader. Sometimes hangs on reboot. Mainline kernel does not support wireless, HDMI, … It is useful for server case scenarios.
USB3 sometimes doesn’t detect high-speed devices properly
PCIe port is not supported: Allwinner H6 has a quirky PCIe controller that doesn’t map the PCIe address space properly to CPU, and accessing the PCIe config space, IO space or memory space will need to be wrapped. As Linux doesn’t wrap PCIe memory space access, it’s not possible to do a proper PCIe controller …
Serial console is enabled by default on µUSB