FilSan

I'll try to respond to your questions as best as I can, but since I don't have that box, I can only guess.
First you mention that 'no matter how long you hold the reset button'.  It isn't a matter of time and the process is that you need to boot with the reset button pressed for about 5 seconds, then after a bit, remove the power and boot with out the reset button pressed.  This second boot should boot into your sd card image.  The first boot holding the reset button is installing 'multiboot' which is a set of changed variables in the uboot environment that essetially changes the boot order.  Then the second boot uses this new uboot environment to boot from the sd card.  Note that you should only need to do the reset button step once (unless or until the uboot environment gets reset to default).
 
You mention the s905x4 chip.  Do not get a box with this.  When it comes to TV boxes, older is better.  So s905x is better supported than s905x2, etc.  This is because it takes a lot of time and effort for the open source community to reverse engineer and get support into mainline linux (as the cpu manufacturers don't generally support linux openly, i.e. they don't release source code, and box manufacturers are even worse at supporting their products).  So the older something is the more likely someone has put in the time to get it somewhat working.  So for the s905x4 there isn't any support yet, and perhaps there may never be.
 
The same general rule (older is better) goes for the other cpu families as well, allwinner and rockchip.  But if you are looking for something in the armbian community I would currently recommend looking at rockchip based boxes.  That is the only cpu family that has an active tv box developer working on support.
 
Then finally, you mention gigabit networking.  I would recomend you set your sights on 100mbit networking.  Generally gigabit networking is implemented in off cpu networking chips that have no/limited support in mainstream linux.  It is very rare that you will get gigabit networking to work on a tv box with armbian.
 
 
Generally the recommendation is to open the box and inspect the chips on the board for their markings and work from there.
 

@FilSan I wanted to comment about the other image you posted/mentioned.  While that sight mentions armbian, that code really has nothing to do with armbian.  Those developers are not involved in the armbian community, nor to they participate in these forums.  They are essentially using the armbian name without permission for their work. 

Hi, a quick start for this TV Box. There are several comments on the 905x3 thread but, for the sake of easiness, I've created this blank new thread.
 
My experience with H96 Max X3:
 
(1) Downloaded (from yandex) and burned Armbian Armbian_20.05.3_Arm-64_buster_dev_5.7.0-rc2-next-20200424_desktop.img 
(2) Copied the /dtb/meson-sm1-sei610-ethfix.dtb into the SD card and modifed uEnv.txt to load that dtb and uncommented the 'APPEND' entry on aml s9xxx section
(3) Made a copy of u-boot.sd into u-boot.ext
(4) Booted with 'the toothpick method', armbian started, basic setup, there you go... perfect armbian desktop 
(5) I did a copy of both the emmc and the working SD into a remote ssh server. (I used a $sudo dd if=/dev/mcblk2 | gzip -1 - | ssh <myuser@myhost> dd of=emmc_backup.gz) and something similar for the SD card
(6) I ran the emmc install script ($sudo /root/install-aml.sh (A warning here: first run I did it from within /boot and it didn't work. On a second run I did it from user home and worked just fine)
(7) SD card removed, clean armbian desktop boot. I did some 'package cleaning' like removing Open Office and some other junk
(8) Made a few configuration changes through armbian-config tool 
(9) I installed tightvnc server, plenty of manuals out there (little warning; I struggled enabling it as a service because of an 'old guide'. Make sure you use systemctl and create the .service file)
 
Not working, for now:
- Wired ethernet negotiated speed at 100Mbps only (It worked at 1 Gbps in Android). 
- No sound: I've read some potential workaround on the 905x3 thread. I'll try to fix it and will edit this.
- No led display on. I've read is kind of tricky but I believe there's a workaround
- Bluetooth: Need additional testing. Linux says it is ok but pairing didn't work.
 
All in all, a quite straight forward install. Please add your comments if you know how to fix the non working stuff or about improving the process.
 
Best of luck!
 
[New findings added on May 11th]
 
- I followed the following bluetooth firmware procedure from @ramoncio and @root-stas:
 
put to folder "/lib/firmware/brcm" file bcm4335c0.hcd from:
https://github.com/kszaq/brcmfmac_sdio-firmware-aml/blob/master/firmware/brcm/bcm4335c0.hcd
with name "BCM4335C0.hcd" and reboot.
 
But while system seems to load the firmware, bluetooth isn't visible or capable to find any discoverable devices so.. I don't think it is really working for me.
 
- I replaced dtb with h96max-x3.dts from @root-stas:
 
It fixed the wired Ethernet and set it to 1Gbps. 
HDMI sound continues not to work. If I plug an USB headset, though, sound will play through headphones.
Tried Lirc to test the remote but service failed to start
  
----------------------------
 
 
 

TV Box Status Information Template Version 1.0
TV Box Name : H96 max x3
CPU: amlogic s905x3
Armbian build file name: Armbian_20.10_Arm-64_focal_current_5.9.0_desktop.img.xz
DTB file used: meson-sm1-sei610-ethfix.dtb
Kernel Version: 5.9.0
Distribution Installed (focal, buster, etc): focal
Working Ethernet (Yes/No): Yes
Max Ethernet Speed that works (100/1000): 1000
Does wifi work (Yes/No): Yes
Does bluetooth work (Yes/No): Yes
Does HDMI audio work (Yes/No): Yes

wifi+bt with BCM4335C0.hcd
Temperature: <70 C
SD boot: No
USB boot : Yes
 

Hello, I found a description for installing Armbian on x96 max plus. I checked it and it works very well. Working for me like personal plex server .
I wonder if there is any way to get control of the front display in Armbian.  Maybe some hint whether display control is possible?
 
Link to Install Linux on X96 max and max plus :
http://mrbluecoat.blogspot.com/2020/10/install-linux-on-x96-max-x96-max.html 
 
 

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https://linux-sunxi.org/UART