Flashing OpenWRT 18.06.1 using both Windows and a macOS

OpenWRT 18.06.1 was released recently, and I took the opportunity to upgrade my router.

Gotcha: Flashing from the LuCI page: Uncheck the "Keep settings" before selecting the firmware, proceed to upgrade, then restore the settings after the upgrade.
I actually didn't do the above (I wondered if it was documented anywhere), so my router came crashing, and I couldn't connect by SSH.

Eventually, I used the following method, which was

1.    Connect TTL to USB cable to the Mac.
2.    Start up putty and connect by serial to the COM port powered by Prolific @ 115 kbps.
3.    Power up WRT1900AC.
4.    Press spacebar when you see lines scrolling in the putty terminal.
5.    Run tftp server on machine at (or IP of machine in instructions below).
6.    Enter following commands into putty/screen terminal:

    setenv firmware_name firmware.img
    setenv ipaddr
    setenv serverip
    setenv netmask
    run flash_pri_image

For step 2, on Mac in a terminal, run:
    screen /dev/cu.usbserial 115200

Note that the machine that's connected to the serial can be a separate machine than that of the TFTP server listed on step 5.
The router would need an Ethernet connection to the TFTP server by a LAN cable.

Published Fri, 24 Aug 2018 @ 8:12 AM by chuacw
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