diff --git a/.github/workflows/build_all.yml b/.github/workflows/build_all.yml
index c39501680c..371806277e 100644
--- a/.github/workflows/build_all.yml
+++ b/.github/workflows/build_all.yml
@@ -134,7 +134,7 @@ jobs:
   flatpak:
     name: "Flatpak"
     container:
-      image: ghcr.io/flathub-infra/flatpak-github-actions:gnome-48
+      image: ghcr.io/flathub-infra/flatpak-github-actions:gnome-49
       options: --privileged
       volumes:
         - /usr/local/lib/android:/usr/local/lib/android
@@ -194,7 +194,12 @@ jobs:
         restore-keys: flatpak-builder-${{ matrix.variant.arch }}-
     - name: Disable debug info for faster CI builds
       run: |
-        sed -i '0,/^finish-args:/s//build-options:\n  no-debuginfo: true\n  strip: true\nfinish-args:/' \
+        sed -i '/^build-options:/a\  no-debuginfo: true\n  strip: true' \
+          scripts/flatpak/io.github.orcaslicer.OrcaSlicer.yml
+      shell: bash
+    - name: Inject git commit hash into Flatpak manifest
+      run: |
+        sed -i "/name: OrcaSlicer/{n;s|buildsystem: simple|buildsystem: simple\n    build-options:\n      env:\n        git_commit_hash: \"$git_commit_hash\"|}" \
           scripts/flatpak/io.github.orcaslicer.OrcaSlicer.yml
       shell: bash
     - name: Inject git commit hash into Flatpak manifest
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8f47f3a944..5c5be1d49f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -173,10 +173,7 @@ option(BUILD_TESTS       "Build unit tests" OFF)
 option(ORCA_TOOLS       "Build Orca tools" OFF)
 
 if (FLATPAK)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++20")
-    set(SLIC3R_PCH OFF CACHE BOOL "" FORCE)
     set(SLIC3R_FHS ON CACHE BOOL "" FORCE)
-    set(BUILD_TESTS OFF CACHE BOOL "" FORCE)
     set(SLIC3R_DESKTOP_INTEGRATION OFF CACHE BOOL "" FORCE)
 endif ()
 
@@ -457,9 +454,12 @@ if (NOT MSVC AND ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" OR "${CMAKE_CXX_COMP
         add_compile_options(-Wno-unknown-pragmas)
     endif()
 
-    # Bit of a hack for flatpak building: compress the debug info with zstd to save space in CI
-    if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 13.0)
-        add_compile_options(-gz=zstd)
+    # Compress the debug info with zstd to save space in Flatpak CI builds
+    if(FLATPAK)
+        if(("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 13.0) OR
+           ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 15.0))
+            add_compile_options(-gz=zstd)
+        endif()
     endif()
 
     if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU" AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 14)
diff --git a/build_flatpak.sh b/build_flatpak.sh
index f7d0b51ba2..225cf25e66 100755
--- a/build_flatpak.sh
+++ b/build_flatpak.sh
@@ -198,22 +198,22 @@ echo -e "${GREEN}All required dependencies found${NC}"
 # Install runtime and SDK if requested
 if [[ "$INSTALL_RUNTIME" == true ]]; then
     echo -e "${YELLOW}Installing GNOME runtime and SDK...${NC}"
-    flatpak install --user -y flathub org.gnome.Platform//48
-    flatpak install --user -y flathub org.gnome.Sdk//48
+    flatpak install --user -y flathub org.gnome.Platform//49
+    flatpak install --user -y flathub org.gnome.Sdk//49
 fi
 
 # Check if required runtime is available
-if ! flatpak info --user org.gnome.Platform//48 &> /dev/null; then
-    echo -e "${RED}Error: GNOME Platform 48 runtime is not installed.${NC}"
+if ! flatpak info --user org.gnome.Platform//49 &> /dev/null; then
+    echo -e "${RED}Error: GNOME Platform 49 runtime is not installed.${NC}"
     echo "Run with -i flag to install it automatically, or install manually:"
-    echo "flatpak install --user flathub org.gnome.Platform//48"
+    echo "flatpak install --user flathub org.gnome.Platform//49"
     exit 1
 fi
 
-if ! flatpak info --user org.gnome.Sdk//48 &> /dev/null; then
-    echo -e "${RED}Error: GNOME SDK 48 is not installed.${NC}"
+if ! flatpak info --user org.gnome.Sdk//49 &> /dev/null; then
+    echo -e "${RED}Error: GNOME SDK 49 is not installed.${NC}"
     echo "Run with -i flag to install it automatically, or install manually:"
-    echo "flatpak install --user flathub org.gnome.Sdk//48"
+    echo "flatpak install --user flathub org.gnome.Sdk//49"
     exit 1
 fi
 
@@ -318,7 +318,7 @@ fi
 MANIFEST="scripts/flatpak/io.github.orcaslicer.OrcaSlicer.yml"
 if [[ "$NO_DEBUGINFO" == true ]]; then
     MANIFEST="scripts/flatpak/io.github.orcaslicer.OrcaSlicer.no-debug.yml"
-    sed '0,/^finish-args:/s//build-options:\n  no-debuginfo: true\n  strip: true\nfinish-args:/' \
+    sed '/^build-options:/a\  no-debuginfo: true\n  strip: true' \
         scripts/flatpak/io.github.orcaslicer.OrcaSlicer.yml > "$MANIFEST"
     echo -e "${YELLOW}Debug info disabled (using temp manifest)${NC}"
 fi
diff --git a/deps/CMakeLists.txt b/deps/CMakeLists.txt
index 492696a58a..1826c029d0 100644
--- a/deps/CMakeLists.txt
+++ b/deps/CMakeLists.txt
@@ -189,6 +189,9 @@ if (NOT IS_CROSS_COMPILE OR NOT APPLE)
             -DCMAKE_C_COMPILER:STRING=${CMAKE_C_COMPILER}
             -DCMAKE_CXX_COMPILER:STRING=${CMAKE_CXX_COMPILER}
             -DCMAKE_TOOLCHAIN_FILE:STRING=${CMAKE_TOOLCHAIN_FILE}
+            -DCMAKE_EXE_LINKER_FLAGS:STRING=${CMAKE_EXE_LINKER_FLAGS}
+            -DCMAKE_SHARED_LINKER_FLAGS:STRING=${CMAKE_SHARED_LINKER_FLAGS}
+            -DCMAKE_MODULE_LINKER_FLAGS:STRING=${CMAKE_MODULE_LINKER_FLAGS}
             -DBUILD_SHARED_LIBS:BOOL=OFF
             ${_cmake_osx_arch}
             "${_configs_line}"
diff --git a/deps/TBB/TBB.cmake b/deps/TBB/TBB.cmake
index 13d40c0573..9b1452d33e 100644
--- a/deps/TBB/TBB.cmake
+++ b/deps/TBB/TBB.cmake
@@ -1,4 +1,4 @@
-if (FLATPAK)
+if (FLATPAK AND "${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
     set(_patch_command ${CMAKE_COMMAND} -E copy ${CMAKE_CURRENT_LIST_DIR}/GNU.cmake ./cmake/compilers/GNU.cmake)
 else()
     set(_patch_command "")
diff --git a/scripts/flatpak/io.github.orcaslicer.OrcaSlicer.yml b/scripts/flatpak/io.github.orcaslicer.OrcaSlicer.yml
index 5bb44df25d..b161f99477 100644
--- a/scripts/flatpak/io.github.orcaslicer.OrcaSlicer.yml
+++ b/scripts/flatpak/io.github.orcaslicer.OrcaSlicer.yml
@@ -1,10 +1,19 @@
 app-id: io.github.orcaslicer.OrcaSlicer
 runtime: org.gnome.Platform
-runtime-version: "48"
+runtime-version: "49"
 sdk: org.gnome.Sdk
+sdk-extensions:
+  - org.freedesktop.Sdk.Extension.llvm21
 command: entrypoint
 separate-locales: true
 rename-icon: OrcaSlicer
+build-options:
+  append-path: /usr/lib/sdk/llvm21/bin
+  prepend-ld-library-path: /usr/lib/sdk/llvm21/lib
+  env:
+    CC: clang
+    CXX: clang++
+    LDFLAGS: "-fuse-ld=lld"
 finish-args:
   - --share=ipc
   - --socket=x11
@@ -38,6 +47,8 @@ modules:
         sha256: e305b9f07f52743ca481da0a4e0c76c35efd60adaf1b0694eb3bb021e2137e39
 
   - name: glu
+    build-options:
+      cxxflags: -Wno-register
     config-opts:
       - --disable-static
     sources:
@@ -70,6 +81,9 @@ modules:
   # Config-opts mirror deps/wxWidgets/wxWidgets.cmake with FLATPAK=ON, DEP_WX_GTK3=ON
   - name: wxWidgets
     buildsystem: cmake-ninja
+    build-options:
+      env:
+        CMAKE_POLICY_VERSION_MINIMUM: "3.5"
     config-opts:
       - -DCMAKE_BUILD_TYPE=Release
       - -DwxBUILD_PRECOMP=ON
@@ -99,6 +113,9 @@ modules:
       - -DwxUSE_LIBJPEG=sys
       - -DwxUSE_LIBTIFF=OFF
       - -DwxUSE_EXPAT=sys
+      - -DCMAKE_EXE_LINKER_FLAGS=-fuse-ld=lld
+      - -DCMAKE_SHARED_LINKER_FLAGS=-fuse-ld=lld
+      - -DCMAKE_MODULE_LINKER_FLAGS=-fuse-ld=lld
     sources:
       - type: git
         url: https://github.com/SoftFever/Orca-deps-wxWidgets
@@ -118,7 +135,10 @@ modules:
           -DDEP_DOWNLOAD_DIR=/run/build/orca_deps/external-packages \
           -DCMAKE_PREFIX_PATH=/app \
           -DDESTDIR=/app \
-          -DCMAKE_INSTALL_PREFIX=/app
+          -DCMAKE_INSTALL_PREFIX=/app \
+          -DCMAKE_EXE_LINKER_FLAGS="-fuse-ld=lld" \
+          -DCMAKE_SHARED_LINKER_FLAGS="-fuse-ld=lld" \
+          -DCMAKE_MODULE_LINKER_FLAGS="-fuse-ld=lld"
       - cmake --build $BUILD_DIR --parallel
       - rm -rf /run/build/orca_deps/external-packages
 
@@ -290,7 +310,10 @@ modules:
           -DFLATPAK=ON \
           -DCMAKE_BUILD_TYPE=Release \
           -DCMAKE_PREFIX_PATH=/app \
-          -DCMAKE_INSTALL_PREFIX=/app
+          -DCMAKE_INSTALL_PREFIX=/app \
+          -DCMAKE_EXE_LINKER_FLAGS="-fuse-ld=lld" \
+          -DCMAKE_SHARED_LINKER_FLAGS="-fuse-ld=lld" \
+          -DCMAKE_MODULE_LINKER_FLAGS="-fuse-ld=lld"
       - cmake --build build_flatpak --target OrcaSlicer -j$FLATPAK_BUILDER_N_JOBS
       - ./scripts/run_gettext.sh
       - cmake --build build_flatpak --target install -j$FLATPAK_BUILDER_N_JOBS
diff --git a/src/slic3r/CMakeLists.txt b/src/slic3r/CMakeLists.txt
index 7ec3215940..4c3bf26737 100644
--- a/src/slic3r/CMakeLists.txt
+++ b/src/slic3r/CMakeLists.txt
@@ -791,9 +791,8 @@ if (UNIX AND NOT APPLE)
         # I don't know why this is needed, but for whatever reason slic3r isn't
         # linking to X11 and webkit2gtk. force it.
         find_package(X11 REQUIRED)
-        find_package(PkgConfig REQUIRED)
         pkg_check_modules(webkit2gtk REQUIRED webkit2gtk-4.1)
-        target_link_libraries (libslic3r_gui ${X11_LIBRARIES} ${webkit2gtk_LIBRARIES})
+        target_link_libraries(libslic3r_gui ${X11_LIBRARIES} ${webkit2gtk_LIBRARIES})
     endif()
     target_include_directories(libslic3r_gui SYSTEM PRIVATE ${GTK${SLIC3R_GTK}_INCLUDE_DIRS} ${LIBSECRET_INCLUDE_DIRS})
     target_link_libraries(libslic3r_gui ${GTK${SLIC3R_GTK}_LIBRARIES} fontconfig ${LIBSECRET_LIBRARIES})
diff --git a/src/slic3r/GUI/MediaPlayCtrl.h b/src/slic3r/GUI/MediaPlayCtrl.h
index bb4e8e448f..f5e5dcddfc 100644
--- a/src/slic3r/GUI/MediaPlayCtrl.h
+++ b/src/slic3r/GUI/MediaPlayCtrl.h
@@ -67,10 +67,10 @@ private:
     static bool get_stream_url(std::string *url = nullptr);
 
 private:
-    static const wxMediaState MEDIASTATE_IDLE = (wxMediaState) 3;
-    static const wxMediaState MEDIASTATE_INITIALIZING = (wxMediaState) 4;
-    static const wxMediaState MEDIASTATE_LOADING = (wxMediaState) 5;
-    static const wxMediaState MEDIASTATE_BUFFERING = (wxMediaState) 6;
+    static inline const wxMediaState MEDIASTATE_IDLE = static_cast<wxMediaState>(3);
+    static inline const wxMediaState MEDIASTATE_INITIALIZING = static_cast<wxMediaState>(4);
+    static inline const wxMediaState MEDIASTATE_LOADING = static_cast<wxMediaState>(5);
+    static inline const wxMediaState MEDIASTATE_BUFFERING = static_cast<wxMediaState>(6);
 
     // token
     std::shared_ptr<int> m_token = std::make_shared<int>(0);