Cannot switch from iGPU to dGPU on Clara AGX

Healthcare & Life Sciences Holoscan SDK
6

I follow the instructions in post Notice: CUDA Linux Repository Key Rotation to update the key (both install the deb package and mannually install the signing key). But it is still not working, when I do sudo apt update, the error message is:

Get:5 https://repo.download.nvidia.com/jetson/dgpu-rm r34.1.2 InRelease [2,544 B]
Err:5 https://repo.download.nvidia.com/jetson/dgpu-rm r34.1.2 InRelease
  The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0D296FFB880FB004

Running sudo nvgpuswitch.py install dGPU has similar results:

Hit:8 http://ports.ubuntu.com/ubuntu-ports focal-security InRelease
Reading package lists... Done
W: GPG error: https://repo.download.nvidia.cn/jetson/dgpu-rm r34.1.2 InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 0D296FFB880FB004
E: The repository 'http://repo.download.nvidia.com/jetson/dgpu-rm r34.1.2 InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.