what is the use of persist.img in android?

Question

While the compilation of Android source we can see an image file named persist.img being created. What is it and for what is it used?

Answer 1

persist.img is "persist" which contains data which shouldn't be changed after the device shipped, for example: calibration data of chips(wifi, bt, camera, etc.), certificates and other security related files. For sure even it's "persist" you still can replace it via fastboot, or change things if the devices is rooted, take it for your own risks