While holding the button, connect the tablet to the PC via USB.
To work with firmware on this chipset, you need specific software utilities designed to communicate with Allwinner's bootloader. allwinner a133 firmware work
Before flashing an unknown "compatible" firmware, try to dump your device's original partitions using ADB or a hardware programmer if possible. While holding the button, connect the tablet to
For runtime modification of the device tree without recompiling the kernel, Device Tree Overlays (DTO) provide a powerful mechanism. Overlays are particularly useful for: While holding the button