Download latest stock firmware for Onda V989 Octa Core Tablet from here or from here. You can root it with this tool.
Firmware： V989 Core8_v2.0_v4Model： Onda V989 Octa Core Tablet Image file size: 451 MBPlatform: A31sOnda V989 Octa Core Tablet Specs
CPU: A31s Quad Core
GPU: Power VR SGX544
RAM 1GB,DDR3
Storage 16GB
Screen: G+G Capacitive Touchscreen, 1024*768 High-resolution Screen
Size: 9.7 inch
Display: HD TFT Screen
Resolution: 1024*768 Pixels
Visible Angle: 178°
Dual Camera Front camera, 2.0 Megapixels Back camera, 2.0 Megapixels
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