Got the cellphone from my old friend, According to his description, We think the next steps should be done by order in my experience. Connecting it to computer with Apple date cable , brush it with the latest version of iTunes when ensure the enough power-supply. we doubt the fault is caused by baseband CPU and 19.2 crystal oscillator, let us check it, And another words, it also can be caused by cable/port or poor Wi-Fi network.
Picture 9-7-1
To find out if the baseband caused the problem, you can replace the new iPhone baseband CPU, and the brush it again, see if iTunes will reports unknown error -1. If it does report an unknown error -1, this indicates that the original baseband damage caused that problem.
Picture 9-7-2
To determine whether it is a 19.2M problem, you can directly replace the new 19.2 crystal oscillator, and then use iTunes to brush it again.
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To check whether it is caused by poor Wi-Fi. Disconnect Wi-Fi both on your computer and iPhone and try to connect them to the network after some time. Next, give another network a same try if it is there.
The above is worth noting that the damaged baseband power supply also can cause this fault. In a word, the error will be fixed after we finished the above operation.
