VPI package not found

I have the same problem on AGX Xavier, Jetpack 4.6 and Ubuntu 18.04.6 LTS:

W: Skipping acquire of configured file 'r34.1/binary-arm64/Packages' as repository 'https://repo.download.nvidia.com/jetson/x86_64 bionic InRelease' doesn't have the component 'r34.1' (component misspelt in sources.list?)
W: Skipping acquire of configured file 'r34.1/i18n/Translation-en' as repository 'https://repo.download.nvidia.com/jetson/x86_64 bionic InRelease' doesn't have the component 'r34.1' (component misspelt in sources.list?)
W: Skipping acquire of configured file 'r34.1/binary-arm64/Packages' as repository 'https://repo.download.nvidia.com/jetson/x86_64 bionic InRelease' doesn't have the component 'r34.1' (component misspelt in sources.list?)
W: Skipping acquire of configured file 'r34.1/i18n/Translation-en' as repository 'https://repo.download.nvidia.com/jetson/x86_64 bionic InRelease' doesn't have the component 'r34.1' (component misspelt in sources.list?)

By looking at Index looks like repository link needs to be adjusted to specific device and release version, e.g. for AGX Xavier (T194) this could be:

sudo add-apt-repository 'deb https://repo.download.nvidia.com/jetson/t194 bionic r32.6'

but it doesn’t work either:

Get:4 https://repo.download.nvidia.com/jetson/common r32.6 InRelease [2555 B]
Get:5 https://repo.download.nvidia.com/jetson/t194 r32.6 InRelease [2547 B]        
Hit:6 http://ports.ubuntu.com/ubuntu-ports bionic-backports InRelease              
Err:7 https://repo.download.nvidia.com/jetson/t194 bionic Release
  404  Not Found [IP: 23.59.250.97 443]
Hit:8 http://ports.ubuntu.com/ubuntu-ports bionic-security InRelease
Reading package lists... Done                     
E: The repository 'https://repo.download.nvidia.com/jetson/t194 bionic Release' does not have a Release file.

Any hints?