The hidden JTAG in your Qualcomm/Snapdragon device’s USB port

“On at least one production device (the OnePlus 6) EUD appears to be disabled via fuse, and yet it just works anyway.”

Almost every Qualcomm chip since 2018 has CPU debugging over a plain USB cable. Qualcomm kept the tools for itself and paying partners until kernel developers pushed back. The code it released would not build and was 11,000 commits behind upstream. On the OnePlus 6, the feature that fuses should disable still works.