I'm deploying Tinker Board 3S units in an embedded product where physical debug interfaces need to be locked down for security.

I want to completely disable the debug UART console (3-pin header, ttyFIQ0 @ 1500000 baud) so that no shell access or boot log output is possible through the serial port.

What I've considered so far:
- Removing "console=ttyFIQ0,1500000" from the kernel command line
- Masking getty@ttyFIQ0.service
- Disabling the UART node in the device tree (status = "disabled")

My questions:
1. Is removing the kernel console parameter + masking getty sufficient, or does U-Boot itself also output to this UART before the kernel takes over? If so, is there a way to silence U-Boot output as well?
2. Is there a recommended device tree overlay approach to fully disable this UART on the RK3566?
3. Are there any side effects to disabling this UART (e.g., boot failures, watchdog issues)?

Environment:
- TinkerOS Debian on eMMC
- Headless deployment, SSH-only access over Ethernet

Any guidance or experience with production hardening on TB3S would be appreciated. Thanks!

I have tried to build Debian for Tinker Board 3s by following the guide at https://github.com/TinkerBoard/TinkerBoard/wiki/Tinker-Board-3-&-3S

After building and flashing image, Debian can boots up and most of features function properly. But I can not play audio via 3.5 mm port:
Some debug information:

root@linaro-alip:/# aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: rockchiphdmi [rockchip,hdmi], device 0: fe400000.i2s-i2s-hifi i2s-hifi-0 [fe400000.i2s-i2s-hifi i2s-hifi-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

root@linaro-alip:/# dmesg | grep sound
[    4.011331] rk-multicodecs rk809-sound: Failed to get ADC channel
[    4.013325] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    4.015123] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    4.621126] rk-multicodecs rk809-sound: Failed to get ADC channel
[    4.623107] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    4.625071] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    4.637447] rk-multicodecs rk809-sound: Failed to get ADC channel
[    4.639581] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    4.641652] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    4.649570] rk-multicodecs rk809-sound: Failed to get ADC channel
[    4.653490] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    4.656981] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    4.738595] rk-multicodecs rk809-sound: Failed to get ADC channel
[    4.740769] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    4.744236] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    4.751415] rk-multicodecs rk809-sound: Failed to get ADC channel
[    4.754619] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    4.758382] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    4.833968] rk-multicodecs rk809-sound: Failed to get ADC channel
[    4.836622] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    4.839072] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    5.043269] rk-multicodecs rk809-sound: Failed to get ADC channel
[    5.045282] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    5.048308] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    5.668399] rk-multicodecs rk809-sound: Failed to get ADC channel
[    5.670634] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    5.672530] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    7.484887] rk-multicodecs rk809-sound: Failed to get ADC channel
[    7.516061] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    7.516070] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    7.555597] rk-multicodecs rk809-sound: Failed to get ADC channel
[    7.555795] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    7.555798] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    7.639002] rk-multicodecs rk809-sound: Failed to get ADC channel
[    7.761508] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    7.763343] rk-multicodecs rk809-sound: Audio routing invalid/unspecified
[    9.902650] rk-multicodecs rk809-sound: Failed to get ADC channel
[    9.904733] rk-multicodecs rk809-sound: ASoC: Property 'rockchip,audio-routing' does not exist or its length is not even
[    9.906440] rk-multicodecs rk809-sound: Audio routing invalid/unspecified

When try to flash official image from https://tinker-board.asus.com/download-list.html?product=tinker-board-3, I can play audio via 3.5 port normally.

Did any one face the same issue ? Please help me !!!

I just bought a Tinkerboard 3S, to investigate the upgrade of an application build on the Tinkerboard S R2.0. On the previous version I used the armbian OS, but this is not available yet fir the 3S.

When I go to the download page (https://tinker-board.asus.com/download-list.html?product=tinker-board-3) no download options/actions occur after selecting the required product.

Where can I download an image to start from?

Thanks,

Luc

I try to activate i2s on my thinkerboard 3S. 

Situation: Tinker Board 3/3S Debian 11 (kernel 5.10) V.1.0.7

Updated: /boot/config.txt

intf:i2s3_2ch=on

Direct connected i2s MEMS microphone, custom build on PCB, worked on tinkerboard S R2.0.

Pins, power and ground

Mic BCLK to pin 12
Mic DOUT to pin 38
Mic LRCL to pin 35

Updated the asound.conf to (based on chatGPT):

pcm.!default {
    type hw
    card 0
    device 0
}

ctl.!default {
    type hw
    card 0
}

alsa installed

aplay -l doesn't list capture devices

What am I missing?