[Bug 2100710] [NEW] apt fails installing wireless-regdb when using pc-kernel (snap) due to read-only filesystem

[Lukas Mayer]

Public bug reported:

# System environment
Ubuntu 24.04.2 LTS using pc-kernel snap


# Expected behaviour
When updating the system with apt, the upgrade should be able to install all packages. 

# Actual behaviour
When using apt, the upgrade of 'wireless-regdb' fails, when using the pc-kernel (snap) because it cannot unpack the regulator.db into the kernel firmware or apt should be aware that a read-only filesystem when using the pc-kernel (snap) is to be expected. If the regulatory.db is provided be the snap package instead, the *.deb package for wireless-regdb should not be included in the installation.

```
Unpacking wireless-regdb (2024.07.04-0ubuntu1~24.04.1) over (2022.06.06-0ubuntu2) ...
dpkg: error processing archive /var/cache/apt/archives/wireless-regdb_2024.07.04-0ubuntu1~24.04.1_all.deb (--unpack):
 unable to create '/lib/firmware/regulatory.db.dpkg-new' (while processing './lib/firmware/regulatory.db'): Read-only file system
dpkg: error while cleaning up:
 unable to remove newly-extracted version of '/lib/firmware/regulatory.db': Read-only file system
Errors were encountered while processing:
 /var/cache/apt/archives/wireless-regdb_2024.07.04-0ubuntu1~24.04.1_all.deb

```

# Solutions that I have tried
Uninstalling package 

```
sudo dpkg --remove --force-remove-reinstreq wireless-regdb
dpkg: warning: overriding problem because --force enabled:
dpkg: warning: package is in a very bad inconsistent state; you should
 reinstall it before attempting a removal
(Reading database ... 101535 files and directories currently installed.)
Removing wireless-regdb (2022.06.06-0ubuntu2) ...
dpkg: error processing package wireless-regdb (--remove):
 cannot remove '/lib/firmware/regulatory.db.p7s': Read-only file system
Processing triggers for man-db (2.12.0-4build2) ...
Errors were encountered while processing:
 wireless-regdb

```

ProblemType: Bug
DistroRelease: Ubuntu 24.04
Package: apt 2.7.14build2
ProcVersionSignature: Ubuntu 6.8.0-54.56-generic 6.8.12
Uname: Linux 6.8.0-54-generic x86_64
ApportVersion: 2.28.1-0ubuntu3.3
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Sun Mar  2 17:02:33 2025
ProcEnviron:
 LANG=de_DE.UTF-8
 PATH=(custom, no user)
 SHELL=/bin/bash
 TERM=xterm-256color
SourcePackage: apt
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: apt (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug noble

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https://bugs.launchpad.net/bugs/2100710

Title:
  apt fails installing wireless-regdb when using pc-kernel (snap) due to
  read-only filesystem

Status in apt package in Ubuntu:
  New

Bug description:
  # System environment
  Ubuntu 24.04.2 LTS using pc-kernel snap

  
  # Expected behaviour
  When updating the system with apt, the upgrade should be able to install all packages. 

  # Actual behaviour
  When using apt, the upgrade of 'wireless-regdb' fails, when using the pc-kernel (snap) because it cannot unpack the regulator.db into the kernel firmware or apt should be aware that a read-only filesystem when using the pc-kernel (snap) is to be expected. If the regulatory.db is provided be the snap package instead, the *.deb package for wireless-regdb should not be included in the installation.

  ```
  Unpacking wireless-regdb (2024.07.04-0ubuntu1~24.04.1) over (2022.06.06-0ubuntu2) ...
  dpkg: error processing archive /var/cache/apt/archives/wireless-regdb_2024.07.04-0ubuntu1~24.04.1_all.deb (--unpack):
   unable to create '/lib/firmware/regulatory.db.dpkg-new' (while processing './lib/firmware/regulatory.db'): Read-only file system
  dpkg: error while cleaning up:
   unable to remove newly-extracted version of '/lib/firmware/regulatory.db': Read-only file system
  Errors were encountered while processing:
   /var/cache/apt/archives/wireless-regdb_2024.07.04-0ubuntu1~24.04.1_all.deb

  ```

  # Solutions that I have tried
  Uninstalling package 

  ```
  sudo dpkg --remove --force-remove-reinstreq wireless-regdb
  dpkg: warning: overriding problem because --force enabled:
  dpkg: warning: package is in a very bad inconsistent state; you should
   reinstall it before attempting a removal
  (Reading database ... 101535 files and directories currently installed.)
  Removing wireless-regdb (2022.06.06-0ubuntu2) ...
  dpkg: error processing package wireless-regdb (--remove):
   cannot remove '/lib/firmware/regulatory.db.p7s': Read-only file system
  Processing triggers for man-db (2.12.0-4build2) ...
  Errors were encountered while processing:
   wireless-regdb

  ```

  ProblemType: Bug
  DistroRelease: Ubuntu 24.04
  Package: apt 2.7.14build2
  ProcVersionSignature: Ubuntu 6.8.0-54.56-generic 6.8.12
  Uname: Linux 6.8.0-54-generic x86_64
  ApportVersion: 2.28.1-0ubuntu3.3
  Architecture: amd64
  CasperMD5CheckResult: pass
  CurrentDesktop: ubuntu:GNOME
  Date: Sun Mar  2 17:02:33 2025
  ProcEnviron:
   LANG=de_DE.UTF-8
   PATH=(custom, no user)
   SHELL=/bin/bash
   TERM=xterm-256color
  SourcePackage: apt
  UpgradeStatus: No upgrade log present (probably fresh install)

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