Comment 5 for bug 1885638

IMO Curtin really should always require partition numbers.

In subiquity, the existing system is probed and a storage config yaml is generated describing the detected system at boot; This allows subiquity/curtin to ensure the preserving a particular partition (say 3 on sda) remains the same.

In your scenario where you're "editing the system configuration" via early_stages is breaking the contract between subiquity's probe and the config it sends when preserving existing layouts to curtin.

Are you working around something that's not working that can be done with the early partitioning?