The H6 CPU frequency has ben soft-capped at 1,48 GHz to avoid thermal throttling too fast. This limit can be lifted by editing
/etc/default/cpufrequtils and set
Warning Adding proper cooling is highly recommended.
Some H6 SoC based boards (like Pine H64 Model a, discontinued) are shipped with a PCIe slot. This slot can and will not be supported by Armbian as it has to be considered as broken by design. Linux-Sunxi writes about this:
Allwinner H6 has a quirky PCIe controller that doesn’t map the PCIe address space properly (only 64k accessible at one time) to CPU, and accessing the PCIe config space, I/O 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 driver for H6. The BSP kernel modifies the driver to wrap the access, so it’s also not generic, and only devices with modified driver will work.