As switching the active partitions currently doesn't work anymore if an update to the latest OEM version was already done, I created an additional image:
This image supports booting from the second partition (and only from the second partition). Any sysupgrade in this image will write it to the first partition and change the boot settings to start from the first partition afterwards. This also means that both partitions will contain OpenWrt afterwards.
The flash procedure would be the following:
- First, try to flash the official OpenWrt recovery image from the firmware selector using the recovery web interface
- If it works, you're done and can stop reading here
- If it doesn't work, you're currently probably running on the second partition and OpenWrt won't boot
- Flash the recovery image from the link above using the recovery web interface. Now OpenWrt should boot and is accessible via web/ssh.
- Flash the official Openwrt sysupgrade image from the OpenWrt web interface or via SSH.
- OpenWrt will now boot from the second partition and works as usual.