Thanks for your helpful feedback.
Here is a detailed (for people who might not be used to *nix) instructions to flash both partitions.
To flash both partitions (once you are in openwrt), all you have to do is
- Download Full Build version (even for Non-US router) from first post above.
- Copy
openwrt-yyyymmdd.trx
onto a flash drive and plug it into the router - ssh into your router. I use Putty to ssh into the router @ 192.168.1.1
- Mount the usb drive using
mount /dev/sda1 /mnt/
- Locate the file name using
ls /mnt/
- Assuming
openwrt-20200102.trx
is the file name, flash using below commands.
mtd write /mnt/openwrt-20200102.trx firmware
mtd write /mnt/openwrt-20200102.trx failsafe
nvram set bootpartition=0 && nvram set partialboots=0 && nvram commit
Reboot to make sure you have openwrt.