Placing that spi flash chip near the SoC is really stupid, I can tell as an electrical engineer. The SoC can easily heat up to 90 degrees, and flash memory does not like high temperatures for a long time. It could also simply be a bad chip.(this is the case I think) These Chinese tablets are probably filled with the cheapest components they can find, which also results in less stable operation.
Now if more people with dual boot Hi12’s would also report having 12khz noise at 0%-25% back light, I might open up the tablet and check some stuff with my oscilloscope. The audio noise is also simply bad design, but most time difficult to fix because of complex pcb routing.
If the guy from 4pda can’t read the chip, he should replace the chip with a good brand like spansion or microchip. These chips are very easy to find.
EDIT: supercowz beat me to it. I was typing slow on my phone 😛
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