Upgrade was successful using standard web-based OpenWRT firmware upgrade procedure.
New image...
Is Avalon not using opkg and a jffs2-capable firmware? O.o
Does it matter? It's easier to guarantee a complete update if you just image the whole flash; the unit should then exactly match fresh production units.
Well, opkg upgrades would be safer (no risk of bricking) and could be automated (possibly after the user clicks an "Upgrade" button only).