I have noticed strange problem with ap6212: when some device is connected to NanoPi M3 on Bluetooth, Wifi speed drops dramatically. When Bluetooth is off, I have WiFi speed about 2 MB/s. When Bluetooth is turned on, WiFi speed drops slightly, although it is still acceptable... But when some Bluetoot...

boot partition - no root fs - yes Kernel image and initrd file must be on SD, unless you have u-boot with USB support enabled and the u-boot is able to read from USB drive. But root partition may be on USB drive. It may be located on any drive visible by Linux. Root fs is specified in bootargs envir...

Is the 2ndboot.bin image source code available somewhere? The sd-fuse_s5p6818 repository on github contains only prebuilt image.