Cannot transmit anything using the gnuradio module "osmocom Sink"

[haohan9717]

Hello, everyone. I was trying to send signals on BladeRF xA4 using gnuradio module "osmocom Sink" modules. Before that, I have already tried the bladerf-cli code and make sure that my hardware is not broken. But due to the customized functions provided by gnuradio, I would like to know how to use it to send signals using "OsmoSDR" library. For now, the BladeRF is not transmitting anything if I use the "osmocom Sink" module. The gnuradio flowgraphs are here:
https://drive.google.com/file/d/1J3KVFU ... sp=sharing
https://drive.google.com/file/d/1Ay4nTO ... sp=sharing

So I have two following questions:
1. Why cannot I use the "OsmoSDR" in gnuradio to drive the BladeRF for transmission?
2. How can I use two TX channels on BladeRF to transmit signals simultaneously like MIMO?

It will be really helpful if anyone can help me on these questions. Thanks!