Does Deepin use OSTree + OverlayFS? /usr is mounted read-only and I cannot write to /usr/bin

I'm not an expert, but I think the problem is that deepin is immutable, so you cannot change files in the system folders, you can disable it if you need. Don't ask me how 😁

The previous version I was using my own scripts on the folder /bin this time I want just to paste them, was imposible.

What you describe is the protected file system, but what is behind... let's ask the AI :)

This is what UOS AI says (the Deepin Linux build in AI agent).

Yes, Deepin 25 (the "磐石系统" / Solid System) does use both OSTree and OverlayFS as part of its core architecture.

🔹 OSTree (for Atomic Updates & Snapshots)

Deepin 25 uses OSTree as the foundation for its immutable system features:

• Atomic system updates – System updates are pulled via ostree pull from a remote repository, using differential compression to minimize download size.
• Snapshot management – The system automatically creates snapshots before installing applications or updates. Users can also create manual snapshots. If an update fails, the system can roll back instantly to the previous state.
• A/B partition mechanism – OSTree enables a dual-partition layout, allowing safe rollbacks and reducing disk space waste through shared files between snapshots.

(Sources: Search results [3], [4], [6])

🔹 OverlayFS (for "Reassuring Restore" / 无忧还原)

Deepin 25 also uses OverlayFS for the "无忧还原" (Reassuring Restore) feature, designed for public/shared computer scenarios:

• Temporary write layer – User modifications are written to a temporary layer, which is automatically discarded on reboot.
• Configurable whitelist – Directories like /etc/ssh can be whitelisted to persist data across reboots.
• Minimal performance impact – The overlay is designed to be nearly imperceptible to users.