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a customer brought in a 6s plus that was ran over by a car. they want to get it fixed to retrieve the data thats in the phone still. surprisingly the board dosent look bad and the housing wasnt even bent or anything. the issue im having is when i initially connect it to dc power it draws .01a for a second then goes to 0 and stays, until i prompt to boot. it turns on a shows the apple logo for about 3-5 seconds then cuts off again. (while it is on the boot current seems normal.) i havent tried to update or restore because i dont want to risk the data. so far all ive done is measure nand power rails and reball the nand to no avail. i also did a full visual inspection and cant find any cracked or visually damaged components. just posting to get some ideas

It’s a pretty risky approach to just reball the NAND without really understanding what’s wrong with the device. You could damage the chip or the logic board during the process, to the point where it becomes difficult to retrieve data. When dealing with a dead device, spend some time to do at least some rudimentary probing. Check the main power lines and the main PMIC outputs (PPCPU/GPU, SOC, FIXED, SDRAM, NAND etc). If that looks good, then check the main BBPMU outputs. Because the phone was crushed, it may just end up being a few bad solder balls somewhere but before applying tons of heat, try to rule out the easy stuff, like subsystem shorts.