Model: iPhone 6s
Fault phenomenon: The CPU on the moving plate drops a little bit.
Moved the board, removed the CPU and found a spot dropped on top of the CPU.
Look at the point map, the dropped point is on the I2C0_AP_SDA bus, scrape the over-hole point next to it on the microscope, tin it, find a line to scrape as thin as possible, blow the wind gun to blow the fly line on the tin, cure the green oil.
Solder the lower layer, power on normal.
Install the upper layer, move the hard drive, baseband, code piece, brush through normally, move the board over!