Hi, for Ubuntu 21.04:
sudo cp /usr/lib/os-release to /usr/lib/os-release-bionic
sudo cp /usr/lib/os-release to /usr/lib/os-release-hisure
sudo nano /usr/lib/os-release-bionic
# fill in indices for Ubuntu 18 as mentioned above.
When you want to start sdkmanager:
sudo cp /usr/lib/os-release-bionic /usr/lib/os-release
sdkmanager
When you are done:
sudo cp /usr/lib/os-release-hisure /usr/lib/os-release