Hi Michal,
First of all I sent v2 because of dt changes to see 1.1 revision and I have also tested it on real HW.
Just tried your patch v2 against mainline master branch, it still doesn't work on my board. I also checked your mainline-v20200312 branch, it's exactly the same: no output from any UART other than "Debug uart enabled" on UART0 if I enable it in menuconfig as "early UART".
For some reason, that's no enough: I have to manually set CONFIG_DEVICE_TREE because xilinx_zynqmp_virt_defconfig sets it wrong. In any case, behaviour is exactly the same as before.
With latest my queue it should be enough. https://github.com/michalsimek/u-boot/tree/mainline-v20200312
It's the same. CONFIG_DEFAULT_DEVICE_TREE becomes "zynqmp-zcu100-revC" whatever I do, there is no trace of the value specified in the DEVICE_TREE environment variable.
But I think that latest mainline should setup default in ITS properly. You can check it by looking at u-boot.its when build is done and find default configuration option which should point to 1.1 dt.
From the build using your mainline-v20200312 branch:
default = "config_1";
where config_1 is
description = "avnet-ultra96-rev1";
Here are jtag steps I have run.
I haven't set up JTAG yet.
Cheers,
András