I followed these steps. The LED is flashing, and I can access the firmware upload screen. When I select the newest firmware from OpenWrt and press “Upload”, the http connection is reset, and nothing more happens. I can still ping to 192.168.1.1. Is it broken for good?
Also I cannot access the uboot console via serial UART.
Why you cannot access uboot console? Does the serial UART has output at all?
No, the screen stays empty without any output. I tried minicom, screen and kermit. Also the RX/TX leds on the serial adapter do not flash.
First, you need to use a 3.3V USB uart adapter.
Second, you should connect TX, RX and GND correctly. Then there must be output.
I just checked again, sorry my fault. Seems I connected to the PCIE port. Will try again and report success.
I have now connected RX->TX, TX->RX, GND->GND. When I start the AR300 with reset button pressed, the LEDs are not flashing at all. No output on the serial console.
When the serial UART is not connected, I can reset the device and the LEDs are flashig. Then I can connect to http://192.168.1.1 and get the Firmware Update screen. But the connection is reset as soon as I try to upload a firmware file.
Can you give a picture of your uart adapter and the way you connect?
I got one step further. Now I used kermit instead of minicom, now at least there is some output. It says:
U-Boot 1.1.4-g9abb38de (Aug 25 2016 - 08:51:31)
DRAM: ath_ddr_initial_config(219): (16bit) ddr1 init
4 MB
and nothing more. Any more hints?
I know from my AR300M that some uboot loaders seem to not like Windows for some reason. Did you try uploading the firmware from a ubuntu live disk (or something like that)?
I run Debian Linux on my Notebook. No Windows involved.
Can you check if you have set correct baudrate?
It’s set to 115200. And as reported above, I do get some messages now.
If nothing more it seem the router is stuck for some reason.
But if you disconnect uart and uboot still works, it is weird.
I made a little progress. When I disconnect the uart, press the reset button and power cycle, and then reconnect the uart, I get a uboot command prompt where I can execute comands like help or tftpboot. On my laptop I have a tftp server running. How to proceed? I would like to flash the newest openwrt firmware 21.02.1.
Seems your UART adapter has problems. Is it 3.3V, not 5V?
Check here https://docs.gl-inet.com/en/3/dev/uboot/
Yes it is set for 3.3 V.
I solved the problem of unreadable uboot output on my GL-MT300N-V2 using another UART adapter ( The problem is described in this thread:
UBOOT wrong serial speed? - #3 by alzhao )
On the adapter in the blue box PL2303TA - the output uboot unreadable (or nothing is output)
On the PL2303 without box - ok (TXD on adapter connect to RXO on GL-MT300N-V2
)
Indeed uboot works now with another UART adapter. I can enter the uboot console and get the ath> prompt. Can you get me on track to flash a new openwrt 21.02 system?
I tried this: start the httpd in uboot. I get the Firmware screen on 192.168.1.1. When I try to upload a image from the Openwrt site, a lot of lines like
####################################
flow over the uboot console, then stop. In the web browser, the connection is reset.
Actually the ##################### is totally correct. This is the upload process. But after that, it should be able to write to flash. Generally it should be use ***********************.
Can you give a full screenshot of the console output?
Can you refer to this guide Advanced Uboot - GL.iNet Docs
For this one you need to set up a tftp server and use command to flash, not using the web panel.
I got upload the image via tftp, and now it did the write to nand flash. The box is runnung now on 21.02! So the problem is solved. Thank you for your suggestions.