Interupting u-boot process during TFTP install using screen, or other tools like minicom or putty

Installing and Using OpenWrt Network and Wireless Configuration
1

I have a bricked Zyxel GS1900-24E that I’m attempting a U-Boot TFTP installation and following the instructions here.

The device I’m installing from is debian based and I have successfully setup a tftp server with tftpd-hpa and serial console with screen.

When I boot the switch I see the U-boot messages fly by on the console, so the serial console is working.

The instructions state:
Connect serial, power up the switch, interrupt U-boot by hitting the
space bar, and enable the network:

> rtk network on

I can’t seem to interrupt the U-boot to enter the rtk command.

I’ve also tried installing minicom and putty but not able to figure that out either.

I know I’m a novice using the serial console, but could you help me out? Thx

2

You have to flip power switch and during 1st second press space bar.

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3

Thanks for the tip, but I still can’t seem to catch it.

I found this video that shows the process of interrupting the u-boot process using picocom as the serial console, which I liked to look of and switched to.

I can’t seem to interrupt the u-boot process and see the Hit any key to stop autoboot: 0 message sail by.

I’ve tried hammering, hitting and holding the spacebar in vain. I also tried the same with the Enter key, like in the video.

Any other thoughts on how to catch it?

Thanks again.

4

Double check the serial connection - it is possible to wire it in way that you have output but no input.

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5

Thx for the suggestion. I checked the connection and they were fine, but it made me think that I had a usb extension cable on the uart as I didn’t have long enough pinout cables.

I removed the cable from the equation and the problem is solved!

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