Network adapter "dies" without HDMI on S912 box

[Solo761]

Hello all,

First straight to the point. Are there some issues with using Amlogic boxes as headless servers with armbian? For some reason ethernet "dies" if I boot it without HDMI connected and it doesn't "come back" even if I connect it back to the monitor and power it on again. I have to reflash SD card with fresh armbian to get it back up. 
Is this some known issue when using android boxes or is this something else? I tried two DTB files for S912 but there was no change.



Now for the whole story. With prices of SBC currently being what they are I thought to try using one of my old Android boxes for simple server. In this case it was Sunvell T95U Pro box with S912 CPU.

Everything went fine, Armbian booted without problems and, I set static IP for easier SSH connection, it also worked fine. I rebooted it few times it started without issues.
Until I turned it off, disconnected HDMI and USB keyboard and powered it back on as it should be small headless server.

But after I powered it again I couldn't connect via SSH anymore. After connecting back keyboard and monitor I get error on boot "eth0 entered promiscuous mode" and after some time few errors saying something about eth0 PHY (error -19 I think) appear and I can't get it working any more. Eth0 is unusable, I tried setting static address via armbian-config again, but after confirmation I only get these PHY errors. I tried rebooting it, plugging and unplugging LAN cable, using different LAN cable but no change. 
Only way to get it back up is reflashing fresh Armbian to SD card and when that boots up eth0 works again. Until I try to run it again without HDMI connected then it's the same story. 

Only change I did to configuration after boot up was setting static IP, and that works fine, I can connect to "new" IP via SSH fine, until I try to boot it without HDMI...
I tried both bullseye and jammy builds, both have the same issue.

I used images from this link, they should be stable versions

https://armbian.hosthatch.com/dl/aml-s9xx-box/archive/

[SteeMan]

I don't have this box (nor any s912 based box), so I can only suggest you search the archives for similar issues.  I know I have seen threads discuss similar issues (can't boot headless without an hdmi connected for other sbc's, and if I recall correctly the workaround was to buy some sort of null hdmi connector, which tricks the box into thinking an hdmi is connected).

Also, it could be a dtb issue, I would suggest trying all of the s912 based dtbs.

[Solo761]

Sorry for not replying sooner, first day I had a message saying I only can make one post per day 😅.

If this is something that's not unusual for these boxes than that's settled. Nothing to be done about that. I've ordered dummy hdmi plug that should help with these issues.

In the meantime I also tried plugging HDMI to VGA adapter but it didn't trick it into thinking something is connected without VGA cable so no dice. I also tried plugging HDMI splitter out of curiosity, but again, no worky. I also tried few different dtbs but no change. If HDMI is disconnected when booting it doesn't wake up.

But at least I figured how to get LAN back after this. If I remove SD card, let it boot into android and after that reboot to SD card LAN works again. I guess this has something to do with hardware and android "knows" how to restart it.

Edited March 11, 2023 by Solo761

[andarezta]

read this if can help,