Clarification on communication transport between STM32U585 and QRB2210 on UNO Q

[philippe86220]

Hello,
Clarification:

The documentation indicates that the Bridge (RPC layer) can operate over multiple physical transports.
The hardware block diagram of the Arduino UNO Q shows two possible inter-processor connections between the STM32U585 (MCU) and the QRB2210 (MPU):

• LPUART1
• SPI3

Could you please confirm which physical transport is used by the current public firmware, and whether the second one (SPI3) is reserved for future high-speed data exchange?

Thank you.