Hello to all.
Sitting at home is becoming more difficult, but a lot of time for experimentation
Today I launched ROS from a flash drive on the AX3400.
Unfortunately, only the management port works.

Hah, I tried the same on some odd network appliance once, but could not get a link on any interfaces. There was some system-management chip that probably handed that.

All those ports is probably behind a switch-chip/asic and not detected/supported by RouterOS.

Yes exactly. It would be nice if favorite OS worked with ASIC for example - Broadcom Trident. Arista 7050 on this chip. And costs on ebay.com from 300 dollars.

It's a bit sad with all custom appliance platforms, when the support/license runs out, then it's basically scrap. In some cases you can get a Linux-distro working but it's hard with the switch-chips (documentation/SDK is often under NDA).