Pls help! Not booting no UART message at all

It’s fine yesterday, but when I try to reboot, it just died.

The power LED is on but nothing on the UART at all.

Maybe a dumb question but have you tried the other port? There are two tty’s, one is the JTAG the other the debug UART. The former will never show any output if you connect to it with a terminal.

Thank you for the reply.
I have the USB UART debug cable that came from the original box.

I would second the suggestion about the other tty. If /dev/ttyUSB0 doesn’t work, then try /dev/ttyUSB1.

Also, if you have an ethernet cable attached, check your local router, maybe it came up and is on the net, and you can get the IP address from there. Though if you don’t have ssh up you will need the serial console working first to enable ssh.

There are also the leds on the board which cycle through different colors as it boots if you are using a recent SiFive OpenEmbedded image. I’m not sure exactly when that was added. But anyways, if you see the leds changing colors then it is booting.

I have the USB UART debug cable that came from the original box.

Yes, sorry if I was unclear, I meant /dev/ttyUSB1 instead of /dev/ttyUSB0, there’s only one physical port on the Unmatched board that can be used for this and that’s the correct cable :slight_smile:

@mzh it looks like you may be using a symlink method of accessing the ttyUSB port and there seems to be a wildcard in the command from the picture you posted which seems like a potential issue.

Can you trying connecting direct to ttyUSB0/ttyUSB1 instead of using the symlink in the screen command?

Sometimes screen program gets in a bad state and a reboot (or the correct screen commands) can recover the functionality. Have you tried rebooting the host machine?

What color is the D2 LED? It’s an RGB LED that changes color through the boot process and can be an indicator if the board is hanging.

Thanks @vmedea @Jim
I changed to ttyUSB1 it works again and it’s my ethernet cable broken so I thought it’s the board is down.

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