FYI, if anyone is interested in advancing Armbian support for H616, I just fixed reboot issue on mainline kernel for OrangePi Zero2. In fact, I started collecting H616 patches in hope to create LibreELEC image. Patches can be found here: https://github.com/jernejsk/linux-1/commits/h616-full
Note: U-Boot needs this hack: https://github.com/jernejsk/u-boot/commit/d420184997f302f546bb0862b1774cca6b43fb9a Without it, Linux will hang at loading Panfrost driver.