Status: WIP, ready for review. So far tested only in VirtualBox – I need help testing on real hardware (USB, Thunderbolt, NVMe/SSD, devices with Secure Boot/TPM, reboot/shutdown scenarios, etc.).

In this PR, I’ve created the Firmware window in mintupdate (GTK3) to get as close as possible to GNOME Firmware’s UX and feature set, while staying within GTK3 limitations.

What’s new:

• Device details – name, vendor, version + extra fields (Minimum Version, Bootloader Version, Branch, Install Duration, Flashes Left, Lock Status). GUIDs and flags are placed in expanders, GUIDs shown in monospace. Device flags and problems are mapped to readable text.
• Release list + Release Details dialog – includes Summary, XML-cleaned Description, Vendor, Filename, Size, Protocol, Remote/AppStream ID, License, Flags, Install Duration, Update Message, Categories, Issues, Checksums. LicenseRef-proprietary is displayed as “Proprietary”.
• Installation flow – confirmation of action type (Upgrade/Downgrade/Reinstall), info about whether the device will be usable during the update. Warnings for Alternate Branch and Full Disk Encryption (FDE). Handles FwupdRequest after install (Action Required / Further Action Required). Post-install prompt for Reboot/Shutdown based on device flags.
• Install from file (.cab) – GNOME Firmware-like flow: get_details_async(path) → select device → confirm → install_async or CLI fallback.
• LVFS – enable/disable LVFS remote (modify_remote_async), refresh (refresh_remote_async), and “Upload Device List” (JSON preview + copy + upload via API or CLI fallback).
• Progress and statuses – GtkRevealer + GtkProgressBar, extended mapping for Fwupd.Status (Downloading, Installing, Device Read/Write/Erase/Verify, Waiting for auth/user, etc.).
• Actions and shortcuts – menubar (for visible accelerators), shortcuts: Ctrl+R (refresh), Ctrl+I (install from file).
• Fallbacks – where API is unavailable (GIR/fwupd version mismatch), fallback to CLI (fwupdmgr via pkexec). Defensive coding for multiple fwupd/GIR versions.

Limitations:

• GTK3 – missing some components from libadwaita/GTK4;
• No coverage on physical hardware yet – this is where I need help.

Modified files:

• mintupdate/usr/lib/linuxmint/mintUpdate/firmwarewindow.py
• mintupdate/usr/share/linuxmint/mintupdate/firmware.ui

Thanks for reviewing! Any feedback on UX, GNOME Firmware compatibility, and real hardware testing is very welcome.