I tried to setup Jetson TX2 using NVIDIA SDK Manager 1.8.
There is the following description in https://developer.nvidia.com/nvidia-sdk-manager.
System Requirements
Host OS Ubuntu 16.04, 18.04 and 20.04 on x86_64 system
So, I installed NVIDIA SDK Manager on Ubuntu 20.04(Host PC).
But, I could not select JetPack 4.6.1 in NVIDIA SDK Manager.
I installed NVIDIA SDK Manager Ubuntu 18.04(Host PC).
As a result, I could select JetPack 4.6.1.
System Requirements
Host OS Ubuntu 16.04, 18.04 and 20.04 on x86_64 system
I think that the above description causes a misunderstanding.
I hope that NVIDIA revises this description.