Betaflight with XM+ Roll and Yaw erratic

[aloneseeker]

So, I am using Omnibus F4 FC, I soldered and powered up everything, when I connected the receiver, I see the roll and yaw going beserk, without any inputs from transmitter, both those axis keep on, here is the video :

what mistake am I doing? I did setup the RX UART6
FC that I am using:

https://www.banggood.com/9g-30_5x30...2&tagtag_uid=2eb463da470e192dbf4834683a78760f