It generates a real-time log of the communication (handshake) between the tool and your device's preloader/VCOM port.
If the device reboots during the trace, the tool freezes the heatmap at the exact millisecond of the failure, showing you which driver or partition was being accessed last. Why it's a game-changer: Smartphone Flash Tool -runtime Trace Mode-l
This is precisely where becomes indispensable. It allows you to see why the handshake is failing. For example, the trace log might reveal: It generates a real-time log of the communication
The technical function of this mode is to capture the hand-shake sequence between the PC and the MediaTek SoC. When a device is connected via USB, the Boot ROM (or Preloader) initializes and waits for commands. Runtime Trace Mode monitors this initialization process at a lower level than the standard interface. It captures data such as USB endpoint status, buffer sizes, and the specific return codes from the NAND or eMMC memory controller. For developers and technicians, this data is invaluable. For instance, if a flash operation fails at 10%, the trace log can reveal whether the failure was caused by the USB cable unplugging, a voltage drop, or a bad sector on the device's internal storage. It allows you to see why the handshake is failing
The "l" suffix stands for Level l (lowercase L), which typically denotes a specific verbosity level or protocol mode. In most engineer documentation, -runtime Trace Mode-l corresponds to Level L: Low-Level BROM Logging . This mode captures the most granular data—right down to the initialization of the Download Agent (DA) and the negotiation of the USB handshake. Higher modes (like Mode-h) would filter for high-level SBC (Secure Boot Chain) events only, but Mode-l gives raw, unfiltered trace data.