diff --git a/pkgs/desktops/lomiri/development/geonames/1001-geonames-cmake4-compat.patch b/pkgs/desktops/lomiri/development/geonames/1001-geonames-cmake4-compat.patch
new file mode 100644
index 000000000000..e338b8824a9d
--- /dev/null
+++ b/pkgs/desktops/lomiri/development/geonames/1001-geonames-cmake4-compat.patch
@@ -0,0 +1,37 @@
+From 3dea0cc91b579de5e2c9db811f2e9e34079d3733 Mon Sep 17 00:00:00 2001
+From: Mike Gabriel <mike.gabriel@das-netzwerkteam.de>
+Date: Mon, 1 Sep 2025 13:22:26 +0200
+Subject: [PATCH] {CMakeLists.txt,cmake/GtkDocScanGObjWrapper.cmake}: Bump
+ cmake_minimum_required() to version 3.10.
+
+---
+ CMakeLists.txt                    | 2 +-
+ cmake/GtkDocScanGObjWrapper.cmake | 2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 5fbff8a..e7b863e 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -1,4 +1,4 @@
+-cmake_minimum_required(VERSION 3.0)
++cmake_minimum_required(VERSION 3.10)
+ project(geonames VERSION 0.3.1 LANGUAGES C)
+ 
+ include(GNUInstallDirs)
+diff --git a/cmake/GtkDocScanGObjWrapper.cmake b/cmake/GtkDocScanGObjWrapper.cmake
+index b187ebb..b026ed0 100644
+--- a/cmake/GtkDocScanGObjWrapper.cmake
++++ b/cmake/GtkDocScanGObjWrapper.cmake
+@@ -20,7 +20,7 @@
+ 
+ # This is needed for find_package(PkgConfig) to work correctly --
+ # CMAKE_MINIMUM_REQUIRED_VERSION needs to be defined.
+-cmake_minimum_required(VERSION 3.2)
++cmake_minimum_required(VERSION 3.10)
+ 
+ if(NOT APPLE)
+     # We use pkg-config to find glib et al
+-- 
+GitLab
+
diff --git a/pkgs/desktops/lomiri/development/geonames/default.nix b/pkgs/desktops/lomiri/development/geonames/default.nix
index dd6c19d142cb..97d195b3dff9 100644
--- a/pkgs/desktops/lomiri/development/geonames/default.nix
+++ b/pkgs/desktops/lomiri/development/geonames/default.nix
@@ -42,6 +42,12 @@ stdenv.mkDerivation (finalAttrs: {
     "devdoc"
   ];
 
+  patches = [
+    # Fix compat with CMake 4
+    # Remove when https://gitlab.com/ubports/development/core/geonames/-/merge_requests/4 merged & in release
+    ./1001-geonames-cmake4-compat.patch
+  ];
+
   postPatch = ''
     patchShebangs src/generate-locales.sh tests/setup-test-env.sh
   '';