Can you passthrough blheli_32 on serial1 (NOT USB)?

Hello, I was trying to setup blheli_32 passthrough on serial1 after having successfully done it via usb.

But it does not connect (blheli_32 just freezes), can it be done? Should i change more than SERVO_BLH_PORT ?

I am using kakute F7 AIO v1.5, here are my params : blheli_serial1_not_working.param (20.2 KB)