Vaillant hrPRO ignores FlowTempDesired setpoint via eBUS (defaults to physical potentiometer)

[vladimirtodic1-cmd]

Hi everyone,
I am using an ESP32 eBUS adapter (v6) connected to a Vaillant hrPRO boiler, running ebusd.
Problem:
I am trying to dynamically control the flow temperature using scripts (curl requests to api/v1/ebus/bai/FlowTempDesired). The commands return success, but the boiler completely ignores the setpoint and heats up to the max temperature set on the physical potentiometer (around 36–37°C) instead of sticking to the commanded 30–31°C.
Terminals 3-4 currently have the default bridge installed.
Writing FlowTempDesired does not overwrite the internal logic.
Questions:
Does the hrPRO / BAI board require a specific command (like SetMode, SetModeOverride, or OperatingMode) to delegate flow temperature control strictly to eBUS?
Do I need to send a simulation telegram to make the boiler recognize the ESP32 adapter as a master regulator (like VRC)?
Is there a known workaround for hrPRO boilers with bridged 3-4 terminals to achieve smooth modular flow temperature setpoints via eBUS without manually turning the knob?
Thanks in advance for any insights!