honentan You can either a) provide the information that I asked for (the device-tree filename you are using), or b) provide unrequested info about a Bluetooth node that is present in 99% of Amlogic legacy device-trees that has nothing to do with Ethernet. It's entirely your call what you share (free speech and all that) but only one of the two results in me taking any further interest in the problem.
NB: In legacy Amlogic devices 99.99% use a broadcom chip so we can use upstream and well supported brcmfmac WiFi and brcm BT drivers instead of the out-of-tree hackfest known as "dhd" that provides WiFi/BT in the legacy kernels. The mainline kernel does not use any of the drivers from legacy 3.14/4.9 kernels (which is a good thing).
understood. The dtb file I use is: meson-gxm-q201.dtb. In Android and armbian systems with the 3.14 kernel, the node name in the device-tree directory is bt-dev, and for versions higher than the 3.14 kernel, I haven't seen any one that can start Bluetooth normally. The Bluetooth hardware chip is RTL8723.