diff --git a/MODULE.bazel b/MODULE.bazel
index 67ff2d20..22e8f68e 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -210,6 +210,13 @@ use_repo(
 
 bazel_dep(name = "score_rules_imagefs", version = "0.0.3", dev_dependency = True)
 
+# TODO: Switch back to a released version once the `ext4` rule is available in a tagged release.
+git_override(
+    module_name = "score_rules_imagefs",
+    commit = "b1278766c01d9f4102c24e87b0ce9d035eaed832",
+    remote = "https://github.com/eclipse-score/rules_imagefs.git",
+)
+
 imagefs = use_extension("@score_rules_imagefs//extensions:imagefs.bzl", "imagefs", dev_dependency = True)
 imagefs.toolchain(
     name = "score_qnx_x86_64_ifs_toolchain",
diff --git a/score/itf/plugins/qemu/__init__.py b/score/itf/plugins/qemu/__init__.py
index 071b2a14..47696f6a 100644
--- a/score/itf/plugins/qemu/__init__.py
+++ b/score/itf/plugins/qemu/__init__.py
@@ -80,6 +80,13 @@ def pytest_addoption(parser):
         help="Path to a QEMU disk image (qcow2, wic, or img). "
         "An ephemeral overlay is created so the original image is not modified.",
     )
+    parser.addoption(
+        "--qemu-disk",
+        action="store",
+        default=None,
+        help="Path to an additional disk image to attach to the target as a second block device. "
+        "A qcow2 overlay is created so the original image is not modified.",
+    )
 
 
 @pytest.fixture(scope="session")
@@ -96,6 +103,7 @@ def config(request):
     qemu_kernel = request.config.getoption("qemu_kernel")
     qemu_image = request.config.getoption("qemu_image")
     rootfs = request.config.getoption("qemu_rootfs")
+    disk = request.config.getoption("qemu_disk")
 
     if qemu_image:
         logger.warning(
@@ -108,6 +116,7 @@ def config(request):
         qemu_config=load_configuration(qemu_config),
         qemu_kernel=qemu_kernel,
         qemu_rootfs=rootfs,
+        qemu_disk=disk,
     )
 
 
@@ -115,14 +124,18 @@ def config(request):
 def target_init(config, request, dlt):
     logger.info(f"Starting tests on host: {socket.gethostname()}")
     overlay_path = None
-    if config.qemu_rootfs:
-        overlay_path = _create_overlay(os.path.abspath(config.qemu_rootfs))
+    disk_overlay_path = None
     try:
+        if config.qemu_rootfs:
+            overlay_path = _create_overlay(os.path.abspath(config.qemu_rootfs))
+        if config.qemu_disk:
+            disk_overlay_path = _create_overlay(os.path.abspath(config.qemu_disk))
         with qemu_target(
             Bunch(
                 qemu_config=config.qemu_config,
                 qemu_kernel=config.qemu_kernel,
                 qemu_rootfs=overlay_path,
+                qemu_disk=disk_overlay_path,
             )
         ) as qemu:
             pre_tests_phase(qemu)
@@ -130,3 +143,5 @@ def target_init(config, request, dlt):
     finally:
         if overlay_path and os.path.exists(overlay_path):
             os.unlink(overlay_path)
+        if disk_overlay_path and os.path.exists(disk_overlay_path):
+            os.unlink(disk_overlay_path)
diff --git a/score/itf/plugins/qemu/qemu.py b/score/itf/plugins/qemu/qemu.py
index 4f06905c..49cbc75b 100644
--- a/score/itf/plugins/qemu/qemu.py
+++ b/score/itf/plugins/qemu/qemu.py
@@ -25,6 +25,9 @@
         "network_device": "virtio-net-pci",
         "machine": "pc",
         "block_device": "virtio-blk-pci",
+        # virtio-blk-pci is probed by the guest in the same order the devices are
+        # specified on the command line.
+        "block_device_order": "ascending",
     },
     "virt-aarch64": {
         "architecture": "aarch64",
@@ -32,6 +35,9 @@
         "network_device": "virtio-net-device",
         "machine": "virt,virtualization=true,gic-version=3",
         "block_device": "virtio-blk-device",
+        # virtio-blk-device (virtio-mmio) is probed by the guest in the reverse order
+        # the devices are specified on the command line.
+        "block_device_order": "descending",
     },
 }
 
@@ -55,6 +61,7 @@ def __init__(
         port_forwarding,
         rootfs,
         kernel_cmdline,
+        disk,
     ):
         """Create a QEMU instance with the specified parameters.
 
@@ -67,6 +74,7 @@ def __init__(
         :param list port_forwarding: List of port forwarding configurations.
         :param str rootfs: Optional path to a qcow2 disk image.
         :param str kernel_cmdline: Optional kernel command line string.
+        :param str disk: Optional path to an additional qcow2 disk image.
         """
         if machine not in _SUPPORTED_MACHINES:
             raise ValueError("machine must be one of: " + ", ".join(sorted(_SUPPORTED_MACHINES)))
@@ -78,6 +86,7 @@ def __init__(
         self.__port_forwarding = port_forwarding
         self.__rootfs = rootfs
         self.__kernel_cmdline = kernel_cmdline
+        self.__disk = disk
 
         self.__check_qemu_is_installed()
 
@@ -147,10 +156,10 @@ def __build_qemu_command(self):
             + self.__network_devices_args()
             + self.__port_forwarding_args()
             + self.__kernel_args()
-            + self.__rootfs_args()
+            + self.__disks_args()
         )
 
-    def __kernel_args(self):
+    def __kernel_args(self) -> list[str]:
         if not self.__path_to_kernel_image:
             return []
         args = ["-kernel", self.__path_to_kernel_image]
@@ -158,14 +167,25 @@ def __kernel_args(self):
             args.extend(["-append", self.__kernel_cmdline])
         return args
 
-    def __rootfs_args(self):
-        if not self.__rootfs:
+    def __disks_args(self) -> list[str]:
+        # Order the disks so that, regardless of the guest's probing order, the rootfs
+        # always ends up as the first block device (/dev/vda) in the guest.
+        disks = [self.__rootfs, self.__disk]
+        if self.__arch_config["block_device_order"] == "descending":
+            disks = list(reversed(disks))
+        args = []
+        for id, disk in enumerate(disks):
+            args += self.__disk_args(disk, id)
+        return args
+
+    def __disk_args(self, disk: str, id: int) -> list[str]:
+        if not disk:
             return []
         return [
             "-device",
-            f"{self.__arch_config['block_device']},drive=vd0",
+            f"{self.__arch_config['block_device']},drive=vd{id}",
             "-drive",
-            f"if=none,format=qcow2,file={self.__rootfs},id=vd0",
+            f"if=none,format=qcow2,file={disk},id=vd{id}",
         ]
 
     def __network_devices_args(self):
diff --git a/score/itf/plugins/qemu/qemu_process.py b/score/itf/plugins/qemu/qemu_process.py
index 7f1221a0..765e0379 100644
--- a/score/itf/plugins/qemu/qemu_process.py
+++ b/score/itf/plugins/qemu/qemu_process.py
@@ -30,6 +30,7 @@ def __init__(
         machine,
         rootfs,
         kernel_cmdline,
+        disk,
     ):
         self._path_to_qemu_kernel_image = path_to_qemu_kernel_image
         self._available_ram = available_ram
@@ -39,6 +40,7 @@ def __init__(
         self._machine = machine
         self._rootfs = rootfs
         self._kernel_cmdline = kernel_cmdline
+        self._disk = disk
         self._qemu = Qemu(
             self._path_to_qemu_kernel_image,
             self._available_ram,
@@ -48,6 +50,7 @@ def __init__(
             machine=self._machine,
             rootfs=self._rootfs,
             kernel_cmdline=self._kernel_cmdline,
+            disk=self._disk,
         )
         self._console = None
 
@@ -65,6 +68,8 @@ def start(self):
             logger.info(f"Using QEMU kernel command line: {self._kernel_cmdline}")
         if self._rootfs is not None:
             logger.info(f"Using QEMU root filesystem image: {self._rootfs}")
+        if self._disk is not None:
+            logger.info(f"Using QEMU additional disk image: {self._disk}")
         subprocess_params = {
             "stdin": subprocess.PIPE,
             "stdout": subprocess.PIPE,
diff --git a/score/itf/plugins/qemu/qemu_target.py b/score/itf/plugins/qemu/qemu_target.py
index f5feb55d..43d845d2 100644
--- a/score/itf/plugins/qemu/qemu_target.py
+++ b/score/itf/plugins/qemu/qemu_target.py
@@ -293,6 +293,7 @@ def qemu_target(test_config):
             machine=test_config.qemu_config.qemu_machine,
             rootfs=test_config.qemu_rootfs,
             kernel_cmdline=test_config.qemu_config.qemu_kernel_cmdline,
+            disk=test_config.qemu_disk,
         )
     else:
         process_ctx = nullcontext()
diff --git a/test/integration/BUILD b/test/integration/BUILD
index 66a190ec..27a0257c 100644
--- a/test/integration/BUILD
+++ b/test/integration/BUILD
@@ -231,6 +231,7 @@ py_itf_test(
     tags = [
         "manual",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 py_itf_test(
@@ -252,6 +253,57 @@ py_itf_test(
     tags = [
         "manual",
     ],
+    target_compatible_with = ["@platforms//os:linux"],
+)
+
+py_itf_test(
+    name = "test_ubuntu_disk",
+    srcs = [
+        "test_qemu_disk.py",
+    ],
+    args = [
+        "--qemu-config=$(location @os_images//ubuntu_x86_64:qemu_config)",
+        "--qemu-rootfs=$(location @os_images//ubuntu_x86_64:image)",
+        "--qemu-disk=$(location //test/resources:qemu_disk_image)",
+    ],
+    data = [
+        "//test/resources:qemu_disk_image",
+        "@os_images//ubuntu_x86_64:image",
+        "@os_images//ubuntu_x86_64:qemu_config",
+    ],
+    plugins = [
+        "//score/itf/plugins:qemu_plugin",
+    ],
+    tags = [
+        "manual",
+    ],
+    target_compatible_with = ["@platforms//os:linux"],
+)
+
+py_itf_test(
+    name = "test_ebclfsa_disk",
+    srcs = [
+        "test_qemu_disk.py",
+    ],
+    args = [
+        "--qemu-config=$(location @os_images//ebclfsa_aarch64:qemu_config)",
+        "--qemu-kernel=$(location @os_images//ebclfsa_aarch64:kernel)",
+        "--qemu-rootfs=$(location @os_images//ebclfsa_aarch64:image)",
+        "--qemu-disk=$(location //test/resources:qemu_disk_image)",
+    ],
+    data = [
+        "//test/resources:qemu_disk_image",
+        "@os_images//ebclfsa_aarch64:image",
+        "@os_images//ebclfsa_aarch64:kernel",
+        "@os_images//ebclfsa_aarch64:qemu_config",
+    ],
+    plugins = [
+        "//score/itf/plugins:qemu_plugin",
+    ],
+    tags = [
+        "manual",
+    ],
+    target_compatible_with = ["@platforms//os:linux"],
 )
 
 test_suite(
@@ -260,7 +312,9 @@ test_suite(
         "manual",
     ],
     tests = [
+        ":test_ebclfsa_disk",
         ":test_ebclfsa_ping",
+        ":test_ubuntu_disk",
         ":test_ubuntu_ping",
     ],
 )
diff --git a/test/integration/test_qemu_disk.py b/test/integration/test_qemu_disk.py
new file mode 100644
index 00000000..dc7ed989
--- /dev/null
+++ b/test/integration/test_qemu_disk.py
@@ -0,0 +1,48 @@
+# *******************************************************************************
+# Copyright (c) 2026 Contributors to the Eclipse Foundation
+#
+# See the NOTICE file(s) distributed with this work for additional
+# information regarding copyright ownership.
+#
+# This program and the accompanying materials are made available under the
+# terms of the Apache License Version 2.0 which is available at
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# SPDX-License-Identifier: Apache-2.0
+# *******************************************************************************
+"""Verifies that a second disk, passed to the QEMU plugin via ``--qemu-disk``,
+shows up in the guest, can be mounted and contains the expected content.
+"""
+
+EXPECTED_DISK_CONTENT = "Hello from the QEMU disk image!\n"
+
+# The additional disk is attached as the second virtio block device. The
+# rootfs occupies the first one, so the disk always shows up as /dev/vdb.
+DISK_DEVICE = "/dev/vdb"
+MOUNT_POINT = "/mnt/qemu_disk"
+
+
+def test_disk_device_is_visible(target):
+    exit_code, _ = target.execute(f"test -b {DISK_DEVICE}")
+    assert exit_code == 0, f"Expected block device {DISK_DEVICE} to be present"
+
+
+def test_disk_can_be_mounted_and_has_expected_content(target):
+    exit_code, _ = target.execute(f"mkdir -p {MOUNT_POINT} && mount {DISK_DEVICE} {MOUNT_POINT}")
+    assert exit_code == 0, "Mounting the additional disk failed"
+    try:
+        exit_code, output = target.execute(f"cat {MOUNT_POINT}/qemu_disk_content.txt")
+        assert exit_code == 0
+        assert output.decode("utf-8") == EXPECTED_DISK_CONTENT
+    finally:
+        target.execute(f"umount {MOUNT_POINT}")
+
+
+def test_disk_is_writable(target):
+    exit_code, _ = target.execute(f"mkdir -p {MOUNT_POINT} && mount {DISK_DEVICE} {MOUNT_POINT}")
+    assert exit_code == 0, "Mounting the additional disk failed"
+    try:
+        exit_code, _ = target.execute(f"touch {MOUNT_POINT}/should_be_writable")
+        assert exit_code == 0, "Writing to the disk should work"
+    finally:
+        target.execute(f"umount {MOUNT_POINT}")
diff --git a/test/resources/BUILD b/test/resources/BUILD
index f5700827..7667a04a 100644
--- a/test/resources/BUILD
+++ b/test/resources/BUILD
@@ -11,7 +11,9 @@
 # SPDX-License-Identifier: Apache-2.0
 # *******************************************************************************
 load("@rules_oci//oci:defs.bzl", "oci_image", "oci_load")
+load("@rules_pkg//pkg:mappings.bzl", "pkg_files")
 load("@rules_pkg//pkg:tar.bzl", "pkg_tar")
+load("@score_rules_imagefs//rules/linux:ext4.bzl", "ext4")
 
 filegroup(
     name = "dlt_config",
@@ -99,3 +101,19 @@ oci_load(
         #"@score_itf_examples//:__subpackages__",
     ],
 )
+
+pkg_files(
+    name = "qemu_disk_files",
+    srcs = ["qemu_disk_content.txt"],
+    prefix = "",
+)
+
+ext4(
+    name = "qemu_disk_image",
+    srcs = [":qemu_disk_files"],
+    out = "qemu_disk.ext4",
+    target_compatible_with = ["@platforms//os:linux"],
+    visibility = [
+        "//test:__subpackages__",
+    ],
+)
diff --git a/test/resources/qemu_disk_content.txt b/test/resources/qemu_disk_content.txt
new file mode 100644
index 00000000..04606245
--- /dev/null
+++ b/test/resources/qemu_disk_content.txt
@@ -0,0 +1 @@
+Hello from the QEMU disk image!
diff --git a/test/unit/test_qemu.py b/test/unit/test_qemu.py
index 9610a832..9cc7747e 100644
--- a/test/unit/test_qemu.py
+++ b/test/unit/test_qemu.py
@@ -25,6 +25,7 @@ def _build_qemu(
     path_to_kernel_image=None,
     kernel_cmdline=None,
     rootfs=None,
+    disk=None,
     network_adapters=None,
     port_forwarding=None,
 ):
@@ -44,6 +45,7 @@ def _build_qemu(
         port_forwarding=port_forwarding,
         rootfs=rootfs,
         kernel_cmdline=kernel_cmdline,
+        disk=disk,
     )
 
 
@@ -59,6 +61,7 @@ def test_invalid_machine_is_rejected(mocker):
             port_forwarding=[],
             rootfs=None,
             kernel_cmdline=None,
+            disk=None,
         )
 
 
@@ -99,7 +102,7 @@ def test_kernel_args_are_empty_without_kernel_image(mocker):
 def test_rootfs_args_include_arch_specific_block_device(mocker):
     qemu = _build_qemu(mocker, machine="virt-aarch64", rootfs="/tmp/rootfs.qcow2")
 
-    assert qemu._Qemu__rootfs_args() == [
+    assert qemu._Qemu__disk_args("/tmp/rootfs.qcow2", 0) == [
         "-device",
         "virtio-blk-device,drive=vd0",
         "-drive",
@@ -110,7 +113,41 @@ def test_rootfs_args_include_arch_specific_block_device(mocker):
 def test_rootfs_args_are_empty_without_rootfs(mocker):
     qemu = _build_qemu(mocker)
 
-    assert qemu._Qemu__rootfs_args() == []
+    assert qemu._Qemu__disk_args(None, 0) == []
+
+
+def test_disk_args_include_arch_specific_block_device(mocker):
+    qemu = _build_qemu(mocker, machine="virt-aarch64", disk="/tmp/disk.qcow2")
+
+    assert qemu._Qemu__disk_args("/tmp/disk.qcow2", 1) == [
+        "-device",
+        "virtio-blk-device,drive=vd1",
+        "-drive",
+        "if=none,format=qcow2,file=/tmp/disk.qcow2,id=vd1",
+    ]
+
+
+def test_disk_args_are_empty_without_disk(mocker):
+    qemu = _build_qemu(mocker)
+
+    assert qemu._Qemu__disk_args(None, 0) == []
+
+
+def test_rootfs_and_disk_can_be_combined(mocker):
+    qemu = _build_qemu(mocker, rootfs="/tmp/rootfs.qcow2", disk="/tmp/disk.qcow2")
+
+    assert qemu._Qemu__disk_args("/tmp/rootfs.qcow2", 0) == [
+        "-device",
+        "virtio-blk-pci,drive=vd0",
+        "-drive",
+        "if=none,format=qcow2,file=/tmp/rootfs.qcow2,id=vd0",
+    ]
+    assert qemu._Qemu__disk_args("/tmp/disk.qcow2", 1) == [
+        "-device",
+        "virtio-blk-pci,drive=vd1",
+        "-drive",
+        "if=none,format=qcow2,file=/tmp/disk.qcow2,id=vd1",
+    ]
 
 
 def test_network_args_skip_loopback_and_use_machine_specific_device(mocker):