Search within XDA for "WM8850 firmware". Look for threads from 2014 with attachments.
Place the FirmwareInstall folder and wmt_scriptcmd file directly onto the root of the SD card. eken+w70+v20+wm8850+firmware+link
He slammed his fist on the desk. The archive had captured the page, but not the file. The link was a husk, a signpost pointing to a demolished building. Search within XDA for "WM8850 firmware"
Are you looking to your device after the firmware install, or are you trying to recover a bricked tablet? eken+w70+v20+wm8850+firmware+link