diff --git a/Dockerfile b/Dockerfile
index d0356fc..b74b2c1 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -1,8 +1,8 @@
 FROM ubuntu:24.04
 
-ENV LINUX_KERNEL_VERSION=6.6
-ENV LINUX_KERNEL_BRANCH=stable_20240529
-ENV LINUX_KERNEL_RT_PATCH=patch-6.6.30-rt30
+ENV LINUX_KERNEL_VERSION=6.12
+ENV LINUX_KERNEL_BRANCH=stable_20250702
+ENV LINUX_KERNEL_RT_PATCH=patch-6.12.43-rt12
 
 ENV TZ=Europe/Copenhagen
 RUN ln -snf /usr/share/zoneinfo/$TZ /etc/localtime && echo $TZ > /etc/timezone
diff --git a/Makefile b/Makefile
index 8f104bc..8cb356b 100644
--- a/Makefile
+++ b/Makefile
@@ -70,5 +70,15 @@ build:
 custom:
 	docker run --rm --privileged -it rpi-rt-linux bash
 
+# Extract relevant files for update of existing system.
+kernel_zips:
+	docker images | grep rpi-rt-linux >/dev/null || ( echo "Build image before running this target." && exit 1)
+	docker rm -f tmp-rpi-rt-linux || true
+	docker run -dit --name tmp-rpi-rt-linux rpi-rt-linux
+	docker cp bundle_firmware_and_modules.sh tmp-rpi-rt-linux:/raspios/.
+	docker exec --privileged tmp-rpi-rt-linux /raspios/bundle_firmware_and_modules.sh
+	docker cp tmp-rpi-rt-linux:/raspios/kernel_zips ./
+	docker rm -f tmp-rpi-rt-linux
+
 clean:
 	rm -fr build
diff --git a/bundle_firmware_and_modules.sh b/bundle_firmware_and_modules.sh
new file mode 100755
index 0000000..466c503
--- /dev/null
+++ b/bundle_firmware_and_modules.sh
@@ -0,0 +1,42 @@
+#!/bin/bash
+
+cd /rpi-kernel/linux/
+make INSTALL_MOD_PATH=/raspios/mnt/disk modules_install
+make INSTALL_DTBS_PATH=/raspios/mnt/boot/firmware dtbs_install
+cd -
+
+
+if [ "$ARCH" = "arm64" ]; then
+    echo "arm_64bit=1" >> /raspios/config.txt
+    cp /rpi-kernel/linux/arch/arm64/boot/Image.gz /raspios/mnt/boot/firmware/$KERNEL\_rt.img
+    cp /rpi-kernel/linux/arch/arm64/boot/dts/broadcom/*.dtb /raspios/mnt/boot/firmware/
+    cp /rpi-kernel/linux/arch/arm64/boot/dts/overlays/*.dtb* /raspios/mnt/boot/firmware/overlays/
+    cp /rpi-kernel/linux/arch/arm64/boot/dts/overlays/README /raspios/mnt/boot/firmware/overlays/
+elif [ "$ARCH" = "arm" ]; then
+    echo "arm_64bit=0" >> /raspios/config.txt
+    cp /rpi-kernel/linux/arch/arm/boot/zImage /raspios/mnt/boot/firmware/$KERNEL\_rt.img
+    cp /rpi-kernel/linux/arch/arm/boot/dts/broadcom/*.dtb /raspios/mnt/boot/firmware/
+    cp /rpi-kernel/linux/arch/arm/boot/dts/overlays/*.dtb* /raspios/mnt/boot/firmware/overlays/
+    cp /rpi-kernel/linux/arch/arm/boot/dts/overlays/README /raspios/mnt/boot/firmware/overlays/
+fi
+
+# Redundant files…
+rm -r /raspios/mnt/boot/firmware/broadcom
+
+KERNEL_VERSION=$(ls -1 /raspios/mnt/disk/lib/modules)
+TARGET_DIR="/raspios/kernel_zips"
+MODULES_ZIP="modules.${KERNEL_VERSION}.zip"
+BOOT_ZIP="boot.${KERNEL_VERSION}.zip"
+sed -zne "/[ \n\t]./{q1;}" <<< "$KERNEL_VERSION" || ( echo "Strange modules folder name?!" && exit 1)
+
+mkdir -p "${TARGET_DIR}"
+cd /raspios/mnt/disk
+zip --symlinks -r "${TARGET_DIR}/${MODULES_ZIP}" *
+cd /raspios/mnt/boot/firmware
+zip --symlinks -r "${TARGET_DIR}/${BOOT_ZIP}" *
+
+echo "Done.
+
+1. Unzip '${BOOT_ZIP}' on / (rootfs-partition) and '${MODULES_ZIP}' on /boot/firmware (boot-partition)
+2. Update boot/config.txt with kernel=${KERNEL}_rt.img
+"