None of the other firmwares will work, the only approach that we can suggest is to dump the firmware using this method
http://www.arctablet.com/blog/forum/firmware-development/dumping-firmware-on-arnova-g2-arnova-g3-and-other-rockchip-based-tablets/

We don`t have funds to buy all the tablets, therefore we can not provide firmwares for all of them, this is where the community should step in and provide some support.

There is another way to do it via linux

rkflash tool source code is here, get it
http://sourceforge.net/projects/rkflashtool/

Install libusb-1.0-0-dev and compile:
sudo apt-get install libusb-1.0-0-dev
gcc -o rkflashtool rkflashtool.c -lusb-1.0 -O2 -W -Wall -s

Read the partition layout
sudo ./rkflashtool r 0x0000 0x2000 > /tmp/parm

in the parm file you will find the cmd line which defines the partition layout

Lets take the archos 80 titanium cmd line

CMDLINE: console=ttyFIQ0 androidboot.console=ttyFIQ0 init=/init initrd=0x62000000,0x00800000 mtdparts=rk29xxnand:0x00002000@0x00002000(misc),0x00004000@0x00004000(kernel),0x00008000@0x00008000(boot),0x00008000@0x00010000(recovery),0x000C0000@0x00018000(backup),0x00040000@0x000D8000(cache),0x00002000@0x00118000(kpanic),0x000E0000@0x0011A000(system),-@0x001FA000(userdata)

To dump the files, i used

sudo ./rkflashtool r 0x0011A000 0x000E0000 > /tmp/system.img
sudo ./rkflashtool r 0x00008000 0x00008000 > /tmp/boot.img
sudo ./rkflashtool r 0x00010000 0x00008000 > /tmp/recovery.img
sudo ./rkflashtool r 0x00018000 0x000C0000 > /tmp/backup.img

Those parameters differ from tablet to tablet, don`t use the exact values from above because it will not work on the Gbook

What`s the point in buying a tablet, from which other lets say 200 will profit and you will use that device only for a developing purpose, from those 200, only 20 will say thank you and only one will donate a fiver, personally i spent arround 10 hours to find a way to dump the firmware from the Archos 80 Titanium, on the Archos Cobalt, i spent another 5, On the Arnova 7c g3, i spent around 60 hours to create a CWM, make a new rooted ROM that had full integration of Play Market, another 3 hours to enable the phone function. I could do those things, because i had the tablets, no tablet no firmware, and even when i made the thins available the people are complaining that I don't help more.