The most successful way to revive these tablets is using the HcH - Uberoid WM8850 project. This is a "hybrid" firmware designed to work on many WM8850 tablets.
1. Copy FirmwareInstall and wmt_scriptcmd to the root of a FAT32 formatted SD card. 2. Insert card into the tablet and power it on. 3. The device should automatically detect the script and start the flashing process. eken+w70+v20+wm8850+firmware+link
If you'd like, I can help you for your V2.0 board or find a rooting guide if the version you download isn't pre-rooted. WM8850-MID Tablet Firmware Files and Root Instructions The most successful way to revive these tablets
Significant technical support and legacy firmware links can be found on platforms such as Android Tablet Forum and Early Bird Club. eken+w70+v20+wm8850+firmware+link