Once successful, the device’s screen might remain blank or show a simple "factory" logo. The real proof is in the PC's Device Manager . A new entry should appear, often labeled as a SPRD U2S Diag port or similar. This port number is the "key" used by repair tools to send commands to the phone's internal hardware.
The terminal screen refreshed. The standard boot logo vanished, replaced by a raw, scrolling feed of hexadecimal code. It was the SPD—Signal Processing Daemon. This wasn't the user-friendly operating system; this was the digital subconscious of the device, the low-level brain that usually operated silently in the background. enter diag mode spd
If that fails, try INFO → FACTORY → 0 → 0 → 0 → 0 on the numeric keypad. Once successful, the device’s screen might remain blank