diff --git a/.ci/AppImageBuilder.yml b/.ci/AppImageBuilder.yml
index 69376b511..3d83e2851 100644
--- a/.ci/AppImageBuilder.yml
+++ b/.ci/AppImageBuilder.yml
@@ -45,7 +45,6 @@ AppDir:
     include:
     - libedit2 # if (CLI:BOOL=ON|QT:BOOL=OFF)
     - libevdev2 # if QT:BOOL=ON
-    - libfluidsynth2
     - libfreetype6
     - libgbm1 # if QT:BOOL=ON
     - libgl1 # if QT:BOOL=ON
diff --git a/.ci/build.sh b/.ci/build.sh
index 42790abb8..bde8cb09e 100644
--- a/.ci/build.sh
+++ b/.ci/build.sh
@@ -986,7 +986,8 @@ else
 	sdl_ui=OFF
 	grep -qiE "^QT:BOOL=ON" build/CMakeCache.txt || sdl_ui=ON
 
-	# Build rtmidi without JACK support to remove the dependency on libjack.
+	# Build rtmidi without JACK support to remove the dependency on libjack, as
+	# the Debian libjack is very likely to be incompatible with the system jackd.
 	prefix="$cache_dir/rtmidi-4.0.0"
 	if [ ! -d "$prefix" ]
 	then
@@ -998,6 +999,21 @@ else
 	cmake --build "$prefix_build" -j$(nproc) || exit 99
 	cmake --install "$prefix_build" || exit 99
 
+	# Build FluidSynth without JACK support to remove the dependency on libjack once again.
+	prefix="$cache_dir/fluidsynth-2.3.0"
+	if [ ! -d "$prefix" ]
+	then
+		rm -rf "$cache_dir/fluidsynth-"* # remove old versions
+		wget -qO - https://github.com/FluidSynth/fluidsynth/archive/refs/tags/v2.3.0.tar.gz | tar zxf - -C "$cache_dir" || rm -rf "$prefix"
+	fi
+	cp cmake/flags-gcc.cmake cmake/flags-gcc.cmake.old
+	sed -i -e 's/ -Werror=.*\([" ]\)/\1/g' cmake/flags-gcc.cmake # temporary hack for -Werror=old-style-definition non-compliance on FluidSynth and SDL2
+	prefix_build="$prefix/build-$arch_deb"
+	cmake -G Ninja -D enable-jack=OFF -D enable-sdl2=$sdl_ss -D "CMAKE_TOOLCHAIN_FILE=$toolchain_file" -D "CMAKE_INSTALL_PREFIX=$cwd_root/archive_tmp/usr" -S "$prefix" -B "$prefix_build" || exit 99
+	cmake --build "$prefix_build" -j$(nproc) || exit 99
+	cmake --install "$prefix_build" || exit 99
+	cp -p "$cwd_root/archive_tmp/usr/bin/fluidsynth" fluidsynth
+
 	# Build SDL2 for joystick and FAudio support, with most components
 	# disabled to remove the dependencies on PulseAudio and libdrm.
 	prefix="$cache_dir/SDL2-2.0.20"
@@ -1006,8 +1022,6 @@ else
 		rm -rf "$cache_dir/SDL2-"* # remove old versions
 		wget -qO - https://www.libsdl.org/release/SDL2-2.0.20.tar.gz | tar zxf - -C "$cache_dir" || rm -rf "$prefix"
 	fi
-	cp cmake/flags-gcc.cmake cmake/flags-gcc.cmake.old
-	sed -i -e 's/ -Werror=.*\([" ]\)/\1/g' cmake/flags-gcc.cmake # temporary hack for -Werror=old-style-definition non-compliance
 	prefix_build="$cache_dir/SDL2-2.0.20-build-$arch_deb"
 	cmake -G Ninja -D SDL_SHARED=ON -D SDL_STATIC=OFF \
 		\