As the title states, I have had failed sysupgrades for all stable release versions of 19.07 on my TP-Link TL-WR902AC v1 travel router (ar71xx; not yet available in ath79). It is specifically the 'sysupgrade' images that appear to be problematic, as 19.07.x runs perfectly once I get a proper flash (via tftp).
Has anyone here been using either this exact device or other devices in the ar71xx target family and had similar failures (or successes)? I'm curious if this is related to the target or the specific device. And I'm wondering how we can identify the specific cause of the failure -- my current theory is that there is an issue with the 'sysupgrade' image, but that the sysupgrade functionality itself is not broken
When the device reboots after the flash process, it gets stuck in a reboot-loop of some sort (I have never connected this device via serial, so I don't know exactly what is happening, but the outward symptoms are cycling ethernet port status (plugged into my Mac, I can see the port flapping) and a blink of all the LEDs (simultaneously). I think it happens on ~4-5 second intervals. The client machine (my mac) never gets an IP via DHCP, and even if the client address is set manually in the 192.168.0.0/24 or 192.168.1.0/24 networks, the device does not respond to pings (I tried 192.168.1.1, 192.168.0.1, 192.168.0.254).
When performing sysupgrade via LuCI, I always ensure that I do not keep settings. The file passes the SHA256 checksum (matches the downloads page checksum). I have always been careful to use the sysupgrade image
tl-wr902ac-v1-squashfs-sysupgrade.bin, so I am confident that I am not causing the problem with the wrong image.
I was able to successfully use the sysupgrade process and images for every maintenance release of OpenWrt 18.06.x. However, since 19.07.0, the sysupgrade has failed every time (including from 18.06.5 > 19.07.0 which is why I don't suspect the sysupgrade functionality is broken on this device) and required tftp recovery (which has been easy and successful using the factory image). The exact same failure mode has happened for every subsequent maintenance release (19.07.1, 19.07.2, and now 19.07.3).