Need Allwinner A20 firmware

[RogellParadox]

Hi, I've got a chinese tablet from a national manufacturer and it ends up with two internal memories. One of them, for the system, is only 500 MB storage. So, I'd like to try a new one. I've already tried others too, like A70X, but it didn't detect sd card and had some problems with calibration.
So, here's my tablet's data:

Model: wing-ak27
Firmware version: 1.3 wing_ak27-eng 4.2.2 JDQ39 20130713 test-keys
Android version: 4.2.2
Kernel version: Linux version 3.3.0+ (gcc version 4.6.3 20120201 (prerelease) (crosstool-NG linaro-1.13.1-2012.02-20120222 - Linaro GCC 2012.02) ) #7 SMP PREEMPT Fri Jul 5 20:55:59 CST 2013

Taken from Phoenix Suit 1.10 software

I'd like some roms sugestions, specially because after some time, my tablet stops working (don't know if it's getting old or maybe a root sideeffect).

Or if someone can modify the .img rom file, I could send it.

Thanks in advance.