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diff --git a/test/py/tests/test_fit_verity_sign.py b/test/py/tests/test_fit_verity_sign.py
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+++ b/test/py/tests/test_fit_verity_sign.py
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+# SPDX-License-Identifier: GPL-2.0
+# Copyright 2026 Daniel Golle <[email protected]>
+
+"""Verify that the dm-verity roothash is covered by the FIT configuration
+signature.
+
+A dm-verity protected filesystem image is not hashed by U-Boot; its integrity
+is delegated to the kernel, which trusts the roothash taken from the FIT
+``dm-verity`` subnode. That roothash must therefore be part of the signed
+region of the configuration, otherwise an attacker can replace both the
+filesystem and the roothash while keeping the configuration signature valid.
+
+This test signs a configuration referencing a filesystem image that carries a
+``dm-verity`` subnode, then flips one byte of the roothash and of the salt and
+checks that verification rejects the image. A control tampering a byte that is
+known to be signed confirms that the check is able to detect a broken region.
+
+The FIT pairs a signed configuration with a filesystem image carrying a
+``dm-verity`` subnode:
+
+.. code-block:: devicetree
+
+    images {
+        rootfs-1 {
+            data = /incbin/("rootfs.bin");
+            type = "filesystem";
+            compression = "none";
+            hash-1 {
+                algo = "sha256";
+            };
+            dm-verity {
+                algo = "sha256";
+                data-block-size = <4096>;
+                hash-block-size = <4096>;
+                num-data-blocks = <16>;
+                hash-start-block = <16>;
+            };
+        };
+    };
+
+    configurations {
+        conf-1 {
+            kernel = "kernel-1";
+            loadables = "rootfs-1";
+            signature-1 {
+                algo = "sha256,rsa2048";
+                key-name-hint = "dev";
+                sign-images = "kernel", "loadables";
+            };
+        };
+    };
+
+mkimage builds the dm-verity hash tree when assembling the image and records
+the resulting roothash and salt in the ``dm-verity`` subnode; fit_check_sign
+must reject an image where either was modified after signing.
+"""
+
+import os
+import pytest
+import utils
+
+# 16 blocks of 4096 bytes, matching num-data-blocks/data-block-size below.
+ROOTFS_SIZE = 16 * 4096
+
+ITS = '''
+/dts-v1/;
+/ {
+    description = "verity roothash signing coverage test";
+    #address-cells = <1>;
+
+    images {
+        kernel-1 {
+            description = "kernel";
+            data = /incbin/("kernel.bin");
+            type = "kernel";
+            arch = "arm64";
+            os = "linux";
+            compression = "none";
+            load = <0x40000000>;
+            entry = <0x40000000>;
+            hash-1 { algo = "sha256"; };
+        };
+        rootfs-1 {
+            description = "rootfs";
+            data = /incbin/("rootfs.bin");
+            type = "filesystem";
+            arch = "arm64";
+            compression = "none";
+            hash-1 { algo = "sha256"; };
+            dm-verity {
+                algo = "sha256";
+                data-block-size = <4096>;
+                hash-block-size = <4096>;
+                num-data-blocks = <16>;
+                hash-start-block = <16>;
+            };
+        };
+    };
+
+    configurations {
+        default = "conf-1";
+        conf-1 {
+            description = "signed config";
+            kernel = "kernel-1";
+            loadables = "rootfs-1";
+            signature-1 {
+                algo = "sha256,rsa2048";
+                key-name-hint = "dev";
+                sign-images = "kernel", "loadables";
+            };
+        };
+    };
+};
+'''
+
+VERITY_NODE = '/images/rootfs-1/dm-verity'
+ROOTFS_HASH_NODE = '/images/rootfs-1/hash-1'
+
+
+def flip_prop_byte(ubman, fit, node, prop):
+    """Flip the first byte of a byte-array property in a FIT, in place.
+
+    The property is rewritten with the same length so that no node is
+    relaid out and the signed regions keep their offsets.
+    """
+    val = utils.run_and_log(ubman, 'fdtget -t bx %s %s %s' % (fit, node, prop))
+    bytelist = val.split()
+    bytelist[0] = '%x' % (int(bytelist[0], 16) ^ 0xff)
+    utils.run_and_log(ubman, 'fdtput -t bx %s %s %s %s' %
+                      (fit, node, prop, ' '.join(bytelist)))
+
+
+[email protected]('sandbox')
+[email protected]('fit_signature')
+[email protected]('dtc')
+[email protected]('fdtget')
+[email protected]('fdtput')
+[email protected]('openssl')
+[email protected]('veritysetup')
+def test_fit_verity_roothash_signed(ubman):
+    """The dm-verity roothash must be inside the signed configuration region."""
+    tmpdir = os.path.join(ubman.config.result_dir, 'verity-sign') + '/'
+    if not os.path.exists(tmpdir):
+        os.makedirs(tmpdir)
+    mkimage = ubman.config.build_dir + '/tools/mkimage'
+    fit_check_sign = ubman.config.build_dir + '/tools/fit_check_sign'
+    dtc_args = '-I dts -O dtb -i %s' % tmpdir
+    its = tmpdir + 'verity.its'
+    fit = tmpdir + 'verity.itb'
+    dtb = tmpdir + 'control.dtb'
+
+    # Signing key and empty control dtb to receive the public key.
+    utils.run_and_log(ubman, 'openssl genpkey -algorithm RSA -out %sdev.key '
+                      '-pkeyopt rsa_keygen_bits:2048 '
+                      '-pkeyopt rsa_keygen_pubexp:65537' % tmpdir)
+    utils.run_and_log(ubman, 'openssl req -batch -new -x509 -key %sdev.key '
+                      '-out %sdev.crt' % (tmpdir, tmpdir))
+    with open(tmpdir + 'control.dts', 'w') as f:
+        f.write('/dts-v1/; / { model = "verity-test"; };\n')
+    utils.run_and_log(ubman, 'dtc -O dtb -o %s %scontrol.dts' % (dtb, tmpdir))
+
+    # Payloads. The rootfs must be a whole number of data blocks so mkimage can
+    # build the dm-verity hash tree and compute the roothash.
+    with open(tmpdir + 'rootfs.bin', 'wb') as f:
+        f.write(b'R' * ROOTFS_SIZE)
+    with open(tmpdir + 'kernel.bin', 'wb') as f:
+        f.write(b'KERNEL')
+
+    with open(its, 'w') as f:
+        f.write(ITS)
+
+    # Build and sign. -E keeps the (large) rootfs external, as on a real device.
+    utils.run_and_log(ubman, [mkimage, '-D', dtc_args, '-E', '-f', its,
+                              '-k', tmpdir, '-K', dtb, '-r', fit])
+
+    # Baseline: the freshly signed image must verify.
+    utils.run_and_log(ubman, [fit_check_sign, '-f', fit, '-k', dtb])
+
+    # Control: tampering a byte that is signed (the filesystem image hash value)
+    # must be detected. This proves the check can fail.
+    control = tmpdir + 'control.itb'
+    utils.run_and_log(ubman, 'cp %s %s' % (fit, control))
+    flip_prop_byte(ubman, control, ROOTFS_HASH_NODE, 'value')
+    utils.run_and_log_expect_exception(
+        ubman, [fit_check_sign, '-f', control, '-k', dtb],
+        1, 'Failed to verify required signature')
+
+    # Roothash: tampering the dm-verity digest must be rejected. If the digest
+    # is outside the signed region this check passes and boot is compromised.
+    tampered = tmpdir + 'tamper-digest.itb'
+    utils.run_and_log(ubman, 'cp %s %s' % (fit, tampered))
+    flip_prop_byte(ubman, tampered, VERITY_NODE, 'digest')
+    utils.run_and_log_expect_exception(
+        ubman, [fit_check_sign, '-f', tampered, '-k', dtb],
+        1, 'Failed to verify required signature')
+
+    # Salt: likewise, the salt feeds the dm-verity target and must be signed.
+    tampered = tmpdir + 'tamper-salt.itb'
+    utils.run_and_log(ubman, 'cp %s %s' % (fit, tampered))
+    flip_prop_byte(ubman, tampered, VERITY_NODE, 'salt')
+    utils.run_and_log_expect_exception(
+        ubman, [fit_check_sign, '-f', tampered, '-k', dtb],
+        1, 'Failed to verify required signature')