iOS 11.2.1, External accessory not writing data to MFi device via Lightning connector,
After checking ATS log provided by apple, iPhone is sending bad packet to the hardware only when connected with USB lightning cable. It works perfectly for BT connection.
We have verified the NSOutputStream write: maxLength: api returns success(0) for all write operation. Also, logged the actual bytes information. From application side everything is working. But, When we check with ATS log iPhone USB stack is sending bad packet with 000...... bytes.
This issue is identified from iOS 11.2.1.
This issue appears in "USB Packets" on ATS or in iAP2 link session? If this error in usb packets maybe it is the problem of ATS system, or you can try to use a short lightning connector cable. You might not be able to fit it if this issue is appers in "USB Packets" on ATS, and it is also not count a errors.