I solved this problem, found a hint here: https://github.com/scaleway/initrd/tree/master/Linux 184.
Here is what I did:
- Edit the “Tags” field in the server definition and add “INITRD_POST_SHELL=1” as one (or the only) tag.
- Reboot the server
- Wait until you get a shell
- Change your password using passwd
- CTRL-d to resume booting.
- Test your new password.
- Remove “INITRD_POST_SHELL=1” from your tags