I have a custom board where I am only using the receive path and the TX pins are not wired to the FPGA. Because of this, I've had to make some changes to ad9361.c (attached) to get it to work, because the TX tuning understandably fails. I also use TDD mode.
I just pulled the most recent kernel, and it looks like the "Improve TX QUAD CAL" commits are again giving me issues. I'm just going to not merge in these specific changes for now, but if possible it would be nice if the driver worked in an RX-only setup.