hnyman:

router is apparently detected as v2 but it is definetly v3

The router's type/model detection is based on the currently running firmware (which claims v2).

Perhaps you have originally flashed a wrong firmware to the device? Which exact firmware it is running now?

adrianschmutzler:

ar71xx or ath79?

adrianschmutzler:

Ah, forget about my last question, it's obvious from the screenshot:
You started with ar71xx and tried to install ath79.

The reason for this bug is that in ar71xx the v3 used the boardname of the v2. So, I will send a patch to update the support list for the v3 images in ath79.

adrianschmutzler:

Patch has been applied to master. I will backport it later this week.

If you want to try already, you can build from my staging tree for openwrt-19.07:
https://git.openwrt.org/?p=openwrt/staging/adrian.git;a=shortlog;h=refs/heads/staging-19.07