3uTools-Forum

Its not always hardware , those days mine 3u tools stop flashing all iphones at 20% , whille iTunes will flash OK

3u Tools had some bug or some possible conflict with some PC Software

There can be a lot of issues, but if you try everything like
New Port - Cable - Last Firmware update - Flash with detached LCD ect
then its Compass IC or NAND IC 99% - Hardware

br Formingus

Update to last Itunes version and check will error change to 4013 ?

Regards