There is an issue with the images for Radxa Zero 3 - it seems that UARTs don’t work properly. RX is ok, but there is no chance to send anything with TX. What is interesting, console over UART works perfect but if I want to use UART3 or UART2 with i.e. minicom they don’t send data. Similar problem with image from armbian. The only one which have worked correctly was Ubuntu version by Joshua Riek. Would it be any chance to solve the issue?
Radxa Zero 3W UART TX doesn't work
uart2 is mainly used for debugging serial ports, it is not recommended to use uart2.
have you tested uart3 on our official image ?
Yes, exactly, I started test with your official image and when I noticed the problem, I extended testing to other distributions. I’d be happy to use your official image but the UARTs TX do not work - I’ve teseted UART3 and UART2 and both of them have the same issue - RX works ok, TX doesn’t. I noticed, the same problem is with armbian and dietpi images.
which image did you use ? can you send me a link so that I can reproduce this issue. and please also describe the steps.
The one I used comes from the link: https://radxa.com/products/zeros/zero3w/#downloads. Apart from that the same result I got using armbian and dietpi indicated by https://docs.radxa.com/en/zero/zero3/getting-started/download
( Debian 12 (Bookworm) Home Assistant)
I already solved the problem installing ubuntu from https://joshua-riek.github.io/ubuntu-rockchip-download/boards/radxa-zero3.html with some modifications I did, but I’d prefer to use official distribution from Radxa.
Steps 
- installing image, installing minicom - board receives correctly but doesn’t send anything over TX
Can we expect any update about the issue?
pictures above are the result I tested.
I have hardware and software that is dependent on RX/TX, and it works fine on Radxa zero 3w with official image. I do disable debug console & uboot on UART2. I use uart2 pins 8 and 10 for compatibility reasons so the hardware works on multiple SBC’s. This is deployed on at least 50 Radxa zero’s, so it’s not a one off fluke.
Information on what I do to get UART2 working on the official image is below, but it’s all around allowing the Radxa to boot with pins 8 & 10 attached. I’ve never seen any issues with TX or RX not working once booted.
More information about hardware etc is
https://aqualinkd.github.io
Thanks for the update - yes, indeed it works with this comand “root@radxa-zero3:/home/radxa# while true ;do echo “dfsdfsdfs” > /dev/ttyS3; sleep 1; done”. Before I testet UARTs with minicom and TX did not and still does not work or I do sometthing wrong. In Ubuntu I managed to run the UARTs without any problems and also to change console from UART2 to UART3 doing some changes in u-boot.
This was also my goal to have compatibility with HW - I use Zigbee2MQTT adapter over UART and it is comaptible with some different SBCs.
