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Author Topic: serial console on zero w  (Read 181 times)

Offline vext01

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serial console on zero w
« on: June 10, 2026, 05:01:29 PM »
Hi,

This evening, I've been trying to get a shell over the UART pins on a raspberry pi zero w.

I found this post where the process is discussed:
https://forum.tinycorelinux.net/index.php?topic=24825.msg157785#msg157785

Namely:

  • console=serial0,115200 in cmdline.txt
  • disable-bt overlay in config.txt
  • update mydata.tgz and uncomment the line that runs /usr/bin/startserialtty in /opt/bootlocal.sh (being careful to preserve permissions when you extract)

The system boots and I see the system come up, just there's no login prompt. Suggests getty isn't running.

I also tried without the disable-bt thing, but the result is the same.

I extracted the rootfs and checked that startserialtty exists, it does.

Any ideas?

Offline Paul_123

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Re: serial console on zero w
« Reply #1 on: June 10, 2026, 05:21:03 PM »
the console line in cmdline.txt only outputs the kernel messages.   The a serial shell, you need to start the serial console.   There is a command in /opt/bootlocal.sh, but it is commented out by default.

You will need a monitor and keyboard to do the setup.

Offline vext01

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Re: serial console on zero w
« Reply #2 on: June 10, 2026, 05:35:22 PM »
Hi Paul,

I already uncommented the line in `/opt/bootlocal.sh` by extracting, editing, and re-compresssing mydata.tgz using another linux system. As I said, I was careful to preserve the permissions too.

Alas, no login prompt.

Offline Paul_123

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Re: serial console on zero w
« Reply #3 on: June 10, 2026, 07:10:45 PM »
Connect a monitor and keyboard, so you can see why it’s not working.  You might try to use the actual serial port device, rather than the link serial0.

You also did not mention which image you are using.

Offline patrikg

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Re: serial console on zero w
« Reply #4 on: June 11, 2026, 01:15:41 AM »
You have to also read my inittab thread on this forum to get it right.
Instead of the startserialtty script workaround :)
https://forum.tinycorelinux.net/index.php/topic,21129.15.html
« Last Edit: June 11, 2026, 01:33:05 AM by patrikg »

Offline vext01

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Re: serial console on zero w
« Reply #5 on: June 11, 2026, 09:02:18 AM »
I have a micro hdmi adapter coming today, so that should make debugging easier.

tbh, i may just not bother and get the wifi up and use ssh. I assume it's just a matter of copying (to the sd card via another computer) wpa_supplicant and it's deps into the `optional` and adding it to the onboot list.