I have a firmware that might work for your device (or brick it ). It has been tested by only 1 person before on the A4. I compiled it assuming everything is the same between both devices except the name.
If you really want to take the risk please send me a PM. This is just because it is based on Padavan and not openwrt and was asked before not to share them here.
Again this was only tested once so there is a small chance of bricking your device.