diff --git a/pos_payment_method_cashdro_fix/README.rst b/pos_payment_method_cashdro_fix/README.rst
new file mode 100644
index 0000000..9854e0a
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/README.rst
@@ -0,0 +1,86 @@
+======================
+POS CashDro 18.0 Fixes
+======================
+
+.. |badge1| image:: https://img.shields.io/badge/maturity-Beta-yellow.png
+    :target: https://odoo-community.org/page/development-status
+    :alt: Beta
+.. |badge2| image:: https://img.shields.io/badge/licence-AGPL--3-blue.png
+    :target: http://www.gnu.org/licenses/agpl-3.0-standalone.html
+    :alt: License: AGPL-3
+
+|badge1| |badge2|
+
+The 18.0 migration of ``pos_payment_method_cashdro``
+(`OCA/pos@6a4c251d <https://github.com/OCA/pos/commit/6a4c251d>`_) left three
+uses of the 17.0 API that stop the CashDro integration from working. The module
+has no tests nor tours and needs a physical drawer to be exercised, so nothing
+in the OCA CI catches them.
+
+This module patches the three of them from the outside, without touching the
+OCA sources:
+
+#. ``_cashdro_url()`` reads ``order.selected_paymentline``, replaced in 18.0 by
+   ``order.get_selected_paymentline()``. Reading ``.payment_method`` on the
+   resulting ``undefined`` raises a ``TypeError`` on every payment, which the
+   caller swallows into a generic *"An error occurred while connecting to the
+   cashdro"* message.
+#. The ``add_paymentline`` patch checks ``line.payment_method``, renamed to
+   ``line.payment_method_id`` in 18.0. The condition is never true, so the
+   payment line keeps the default due amount instead of waiting for the amount
+   the customer inserts in the drawer.
+#. ``pos.session._loader_params_pos_payment_method`` is the 17.0 loading API,
+   replaced in 18.0 by ``_load_pos_data_fields`` on each model. The override is
+   dead code, so ``cashdro_host``, ``cashdro_user`` and ``cashdro_password``
+   never reach the front end.
+
+**Table of contents**
+
+.. contents::
+   :local:
+
+Usage
+=====
+
+There is nothing to configure: installing the module is enough.
+
+To check the three fixes on a PoS with a CashDro terminal:
+
+#. Open a PoS session, add a product and go to the payment screen.
+#. Select the CashDro payment method. The payment line must show **0**, not the
+   due amount (fix 2).
+#. The drawer must start the operation and ask for the amount, instead of the
+   *"An error occurred while connecting to the cashdro"* dialog (fixes 1 and 3).
+#. With no CashDro at hand, the browser console tells fix 1 from fix 3 apart:
+   without this module the failure is a ``TypeError: Cannot read properties of
+   undefined (reading 'payment_method')``; with it, a network error against the
+   configured host.
+
+The Python side is covered by the tests. The base module lives outside this
+repo, so the OCA sources have to be on the addons path (see
+``docker-compose.override.yml``, which is local and untracked)::
+
+  docker-compose run --rm odoo odoo -c /etc/odoo/odoo.conf \
+      --addons-path=/mnt/extra-addons,/mnt/oca/pos,/usr/lib/python3/dist-packages/odoo/addons \
+      -d odoo -u pos_payment_method_cashdro_fix --test-enable --stop-after-init
+
+Known issues / Roadmap
+======================
+
+This module is meant to be temporary. The fixes are proposed upstream in
+``upstream/pos_payment_method_cashdro-18.0-fixes.patch``; once they are merged
+in ``OCA/pos`` this module can be uninstalled and removed.
+
+It is written to stay harmless in the meantime: the Python override only adds
+the credential fields that are missing from the loader, and the JavaScript
+patches are idempotent with respect to the fixed upstream code.
+
+The JavaScript side can't be covered by automated tests, as it needs a CashDro
+terminal answering on the network.
+
+Contributors
+============
+
+* `Criptomart <https://criptomart.net>`_:
+
+  * Criptomart
diff --git a/pos_payment_method_cashdro_fix/__init__.py b/pos_payment_method_cashdro_fix/__init__.py
new file mode 100644
index 0000000..8f9e965
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/__init__.py
@@ -0,0 +1,3 @@
+# Copyright 2026 - Today Criptomart
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+from . import models
diff --git a/pos_payment_method_cashdro_fix/__manifest__.py b/pos_payment_method_cashdro_fix/__manifest__.py
new file mode 100644
index 0000000..bbe4598
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/__manifest__.py
@@ -0,0 +1,23 @@
+# Copyright 2026 - Today Criptomart
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+{
+    "name": "POS CashDro 18.0 Fixes",
+    "version": "18.0.1.0.0",
+    "summary": "Fix the 17.0 API leftovers that break pos_payment_method_cashdro on 18.0",
+    "category": "Point of Sale",
+    "license": "AGPL-3",
+    "author": "Criptomart",
+    "maintainers": ["Criptomart"],
+    "website": "https://git.criptomart.net/criptomart/addons-cm",
+    "depends": [
+        "point_of_sale",
+        "pos_payment_method_cashdro",
+    ],
+    "assets": {
+        "point_of_sale._assets_pos": [
+            "pos_payment_method_cashdro_fix/static/src/js/payment_cashdro_fix.esm.js",
+            "pos_payment_method_cashdro_fix/static/src/js/models_fix.esm.js",
+        ],
+    },
+    "installable": True,
+}
diff --git a/pos_payment_method_cashdro_fix/models/__init__.py b/pos_payment_method_cashdro_fix/models/__init__.py
new file mode 100644
index 0000000..58690ef
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/models/__init__.py
@@ -0,0 +1 @@
+from . import pos_payment_method
diff --git a/pos_payment_method_cashdro_fix/models/pos_payment_method.py b/pos_payment_method_cashdro_fix/models/pos_payment_method.py
new file mode 100644
index 0000000..8ec6d8d
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/models/pos_payment_method.py
@@ -0,0 +1,26 @@
+# Copyright 2026 - Today Criptomart
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+from odoo import api
+from odoo import models
+
+CASHDRO_FIELDS = ["cashdro_host", "cashdro_user", "cashdro_password"]
+
+
+class PosPaymentMethod(models.Model):
+    _inherit = "pos.payment.method"
+
+    @api.model
+    def _load_pos_data_fields(self, config_id):
+        """Send the CashDro credentials to the PoS front end.
+
+        `pos_payment_method_cashdro` still declares them through
+        `_loader_params_pos_payment_method`, the 17.0 loading API, which 18.0
+        replaced by this method. That override is dead code, so the front end
+        never receives the host and can't build the CashDro url.
+
+        Only the missing fields are added, so this module stays harmless once
+        the base one is fixed upstream.
+        """
+        fields = super()._load_pos_data_fields(config_id)
+        fields.extend(field for field in CASHDRO_FIELDS if field not in fields)
+        return fields
diff --git a/pos_payment_method_cashdro_fix/readme/CONTRIBUTORS.rst b/pos_payment_method_cashdro_fix/readme/CONTRIBUTORS.rst
new file mode 100644
index 0000000..16df929
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/readme/CONTRIBUTORS.rst
@@ -0,0 +1,3 @@
+* `Criptomart <https://criptomart.net>`_:
+
+  * Criptomart
diff --git a/pos_payment_method_cashdro_fix/readme/DESCRIPTION.rst b/pos_payment_method_cashdro_fix/readme/DESCRIPTION.rst
new file mode 100644
index 0000000..c5f2de1
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/readme/DESCRIPTION.rst
@@ -0,0 +1,22 @@
+The 18.0 migration of ``pos_payment_method_cashdro``
+(`OCA/pos@6a4c251d <https://github.com/OCA/pos/commit/6a4c251d>`_) left three
+uses of the 17.0 API that stop the CashDro integration from working. The module
+has no tests nor tours and needs a physical drawer to be exercised, so nothing
+in the OCA CI catches them.
+
+This module patches the three of them from the outside, without touching the
+OCA sources:
+
+#. ``_cashdro_url()`` reads ``order.selected_paymentline``, replaced in 18.0 by
+   ``order.get_selected_paymentline()``. Reading ``.payment_method`` on the
+   resulting ``undefined`` raises a ``TypeError`` on every payment, which the
+   caller swallows into a generic *"An error occurred while connecting to the
+   cashdro"* message.
+#. The ``add_paymentline`` patch checks ``line.payment_method``, renamed to
+   ``line.payment_method_id`` in 18.0. The condition is never true, so the
+   payment line keeps the default due amount instead of waiting for the amount
+   the customer inserts in the drawer.
+#. ``pos.session._loader_params_pos_payment_method`` is the 17.0 loading API,
+   replaced in 18.0 by ``_load_pos_data_fields`` on each model. The override is
+   dead code, so ``cashdro_host``, ``cashdro_user`` and ``cashdro_password``
+   never reach the front end.
diff --git a/pos_payment_method_cashdro_fix/readme/ROADMAP.rst b/pos_payment_method_cashdro_fix/readme/ROADMAP.rst
new file mode 100644
index 0000000..bab1608
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/readme/ROADMAP.rst
@@ -0,0 +1,10 @@
+This module is meant to be temporary. The fixes are proposed upstream in
+``upstream/pos_payment_method_cashdro-18.0-fixes.patch``; once they are merged
+in ``OCA/pos`` this module can be uninstalled and removed.
+
+It is written to stay harmless in the meantime: the Python override only adds
+the credential fields that are missing from the loader, and the JavaScript
+patches are idempotent with respect to the fixed upstream code.
+
+The JavaScript side can't be covered by automated tests, as it needs a CashDro
+terminal answering on the network. See ``USAGE`` for the manual check.
diff --git a/pos_payment_method_cashdro_fix/readme/USAGE.rst b/pos_payment_method_cashdro_fix/readme/USAGE.rst
new file mode 100644
index 0000000..6499224
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/readme/USAGE.rst
@@ -0,0 +1,21 @@
+There is nothing to configure: installing the module is enough.
+
+To check the three fixes on a PoS with a CashDro terminal:
+
+#. Open a PoS session, add a product and go to the payment screen.
+#. Select the CashDro payment method. The payment line must show **0**, not the
+   due amount (fix 2).
+#. The drawer must start the operation and ask for the amount, instead of the
+   *"An error occurred while connecting to the cashdro"* dialog (fixes 1 and 3).
+#. With no CashDro at hand, the browser console tells fix 1 from fix 3 apart:
+   without this module the failure is a ``TypeError: Cannot read properties of
+   undefined (reading 'payment_method')``; with it, a network error against the
+   configured host.
+
+The Python side is covered by the tests. The base module lives outside this
+repo, so the OCA sources have to be on the addons path (see
+``docker-compose.override.yml``, which is local and untracked)::
+
+  docker-compose run --rm odoo odoo -c /etc/odoo/odoo.conf \
+      --addons-path=/mnt/extra-addons,/mnt/oca/pos,/usr/lib/python3/dist-packages/odoo/addons \
+      -d odoo -u pos_payment_method_cashdro_fix --test-enable --stop-after-init
diff --git a/pos_payment_method_cashdro_fix/static/src/js/models_fix.esm.js b/pos_payment_method_cashdro_fix/static/src/js/models_fix.esm.js
new file mode 100644
index 0000000..51598ff
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/static/src/js/models_fix.esm.js
@@ -0,0 +1,31 @@
+/* Copyright 2026 - Today Criptomart
+   License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+   The `add_paymentline` patch of `pos_payment_method_cashdro` checks
+   `line.payment_method`, renamed to `payment_method_id` in 18.0, so the
+   condition is never met and the line keeps the default due amount instead of
+   waiting for the amount the customer actually inserts in the drawer.
+*/
+
+import { PosOrder } from "@point_of_sale/app/models/pos_order";
+import { patch } from "@web/core/utils/patch";
+
+patch(PosOrder.prototype, {
+    /**
+     * @override
+     * Set the amount to 0 as it's going to be filled by the Cashdro response.
+     */
+    add_paymentline() {
+        const line = super.add_paymentline(...arguments);
+        if (!line) {
+            return line;
+        }
+        if (
+            line.payment_method_id?.use_payment_terminal === "cashdro" &&
+            line.amount > 0 // For refund transactions we need to keep the amount
+        ) {
+            line.set_amount(0);
+        }
+        return line;
+    },
+});
diff --git a/pos_payment_method_cashdro_fix/static/src/js/payment_cashdro_fix.esm.js b/pos_payment_method_cashdro_fix/static/src/js/payment_cashdro_fix.esm.js
new file mode 100644
index 0000000..3410747
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/static/src/js/payment_cashdro_fix.esm.js
@@ -0,0 +1,33 @@
+/* Copyright 2026 - Today Criptomart
+   License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+
+   `_cashdro_url` was left with the 17.0 API in the 18.0 migration of
+   `pos_payment_method_cashdro`: `order.selected_paymentline` no longer exists,
+   so reading `.payment_method` on it throws a TypeError that the caller
+   swallows as a generic connection error. Rewritten with the 18.0 accessors.
+*/
+
+import { PaymentCashdro } from "@pos_payment_method_cashdro/js/payment_cashdro.esm";
+import { patch } from "@web/core/utils/patch";
+
+patch(PaymentCashdro.prototype, {
+    /**
+     * @override
+     * The whole body has to be replaced: the very first statement is the one
+     * that breaks, so there is nothing left to delegate to `super`.
+     */
+    _cashdro_url() {
+        // Cashdro machines don't support safe POST calls, so we're sending
+        // all the data quite unsafely constantly...
+        const order = this.pos.get_order();
+        const method = order.get_selected_paymentline()?.payment_method_id;
+        const host = method && method.cashdro_host;
+        if (!host) {
+            return false;
+        }
+        let url = `${host}/Cashdro3WS/index.php`;
+        url += `?name=${method.cashdro_user}`;
+        url += `&password=${method.cashdro_password}`;
+        return url;
+    },
+});
diff --git a/pos_payment_method_cashdro_fix/tests/__init__.py b/pos_payment_method_cashdro_fix/tests/__init__.py
new file mode 100644
index 0000000..02c4d2e
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/tests/__init__.py
@@ -0,0 +1 @@
+from . import test_load_pos_data_fields
diff --git a/pos_payment_method_cashdro_fix/tests/test_load_pos_data_fields.py b/pos_payment_method_cashdro_fix/tests/test_load_pos_data_fields.py
new file mode 100644
index 0000000..ebee5e4
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/tests/test_load_pos_data_fields.py
@@ -0,0 +1,33 @@
+# Copyright 2026 - Today Criptomart
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from odoo.tests import tagged
+from odoo.tests.common import TransactionCase
+
+from ..models.pos_payment_method import CASHDRO_FIELDS
+
+
+@tagged("post_install", "-at_install")
+class TestLoadPosDataFields(TransactionCase):
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.payment_method = cls.env["pos.payment.method"]
+        # Nothing dereferences it, but we pass a real config when there's one
+        cls.config_id = cls.env["pos.config"].search([], limit=1).id
+
+    def test_cashdro_credentials_are_loaded(self):
+        """The front end can't build the CashDro url without them."""
+        fields = self.payment_method._load_pos_data_fields(self.config_id)
+        for field in CASHDRO_FIELDS:
+            self.assertIn(field, fields)
+
+    def test_no_duplicated_fields(self):
+        """Once the base module is fixed upstream we must not add them twice."""
+        fields = self.payment_method._load_pos_data_fields(self.config_id)
+        self.assertEqual(sorted(fields), sorted(set(fields)))
+
+    def test_fields_exist_on_the_model(self):
+        """Guard against a rename of the credentials in the base module."""
+        for field in CASHDRO_FIELDS:
+            self.assertIn(field, self.payment_method._fields)
diff --git a/pos_payment_method_cashdro_fix/upstream/pos_payment_method_cashdro-18.0-fixes.patch b/pos_payment_method_cashdro_fix/upstream/pos_payment_method_cashdro-18.0-fixes.patch
new file mode 100644
index 0000000..84ca58f
--- /dev/null
+++ b/pos_payment_method_cashdro_fix/upstream/pos_payment_method_cashdro-18.0-fixes.patch
@@ -0,0 +1,133 @@
+From 11c65e8000282b9a761346f1fbff16e09581fc17 Mon Sep 17 00:00:00 2001
+From: Criptomart <ofi@criptomart.net>
+Date: Tue, 11 Aug 2026 13:21:28 +0200
+Subject: [PATCH] [FIX] pos_payment_method_cashdro: leftovers of the 17.0 API
+
+The 18.0 migration kept three uses of APIs that no longer exist, and the
+module has neither tests nor tours (it needs a physical drawer), so the CI
+can't catch them.
+
+* `_cashdro_url()` reads `order.selected_paymentline`, replaced by
+  `order.get_selected_paymentline()` in 18.0. Reading `.payment_method` on
+  the resulting `undefined` throws a TypeError on every payment, which
+  `cashdro_send_payment_request()` swallows into a generic "An error occurred
+  while connecting to the cashdro" dialog.
+
+* The `add_paymentline()` patch checks `line.payment_method`, renamed to
+  `line.payment_method_id` in 18.0, so the payment line is never zeroed and
+  keeps the default due amount instead of the amount the customer inserts.
+
+* `_loader_params_pos_payment_method()` is the 17.0 loading API, replaced in
+  18.0 by `_load_pos_data_fields()` on each model. The override is dead code
+  and the CashDro credentials never reach the front end, so `_cashdro_url()`
+  has no host to build the url with.
+---
+ pos_payment_method_cashdro/__manifest__.py         |  2 +-
+ pos_payment_method_cashdro/models/__init__.py      |  1 -
+ .../models/pos_payment_method.py                   | 11 ++++++++++-
+ pos_payment_method_cashdro/models/pos_session.py   | 14 --------------
+ .../static/src/js/models.esm.js                    |  4 ++--
+ .../static/src/js/payment_cashdro.esm.js           |  3 ++-
+ 6 files changed, 15 insertions(+), 20 deletions(-)
+ delete mode 100644 pos_payment_method_cashdro/models/pos_session.py
+
+diff --git a/pos_payment_method_cashdro/__manifest__.py b/pos_payment_method_cashdro/__manifest__.py
+index 708aac5..c19a642 100644
+--- a/pos_payment_method_cashdro/__manifest__.py
++++ b/pos_payment_method_cashdro/__manifest__.py
+@@ -3,7 +3,7 @@
+ {
+     "name": "PoS Payment Method CashDro",
+     "summary": "Allows to pay with CashDro Terminals on the Point of Sale",
+-    "version": "18.0.1.0.2",
++    "version": "18.0.1.0.3",
+     "category": "Point Of Sale",
+     "website": "https://github.com/OCA/pos",
+     "author": "Tecnativa, Odoo Community Association (OCA)",
+diff --git a/pos_payment_method_cashdro/models/__init__.py b/pos_payment_method_cashdro/models/__init__.py
+index 604d90c..58690ef 100644
+--- a/pos_payment_method_cashdro/models/__init__.py
++++ b/pos_payment_method_cashdro/models/__init__.py
+@@ -1,2 +1 @@
+ from . import pos_payment_method
+-from . import pos_session
+diff --git a/pos_payment_method_cashdro/models/pos_payment_method.py b/pos_payment_method_cashdro/models/pos_payment_method.py
+index 285984a..08a64a1 100644
+--- a/pos_payment_method_cashdro/models/pos_payment_method.py
++++ b/pos_payment_method_cashdro/models/pos_payment_method.py
+@@ -1,6 +1,6 @@
+ # Copyright 2021 Tecnativa - David Vidal
+ # License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+-from odoo import fields, models
++from odoo import api, fields, models
+ 
+ 
+ class PosPaymentMethod(models.Model):
+@@ -16,6 +16,15 @@ class PosPaymentMethod(models.Model):
+     cashdro_user = fields.Char()
+     cashdro_password = fields.Char()
+ 
++    @api.model
++    def _load_pos_data_fields(self, config_id):
++        """The front end needs the credentials to build the CashDro url"""
++        return super()._load_pos_data_fields(config_id) + [
++            "cashdro_host",
++            "cashdro_user",
++            "cashdro_password",
++        ]
++
+     def _onchange_journal_id(self):
+         """Cash payment method force the `use_payment_terminal` to `False` as
+         it's assumed that a cash journal can't have a payment terminal. Let's keep
+diff --git a/pos_payment_method_cashdro/models/pos_session.py b/pos_payment_method_cashdro/models/pos_session.py
+deleted file mode 100644
+index 6123090..0000000
+--- a/pos_payment_method_cashdro/models/pos_session.py
++++ /dev/null
+@@ -1,14 +0,0 @@
+-# Copyright 2024 Tecnativa - David Vidal
+-# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+-from odoo import models
+-
+-
+-class PosSession(models.Model):
+-    _inherit = "pos.session"
+-
+-    def _loader_params_pos_payment_method(self):
+-        result = super()._loader_params_pos_payment_method()
+-        result["search_params"]["fields"].extend(
+-            ["cashdro_host", "cashdro_user", "cashdro_password"]
+-        )
+-        return result
+diff --git a/pos_payment_method_cashdro/static/src/js/models.esm.js b/pos_payment_method_cashdro/static/src/js/models.esm.js
+index d228f08..d1ee2f7 100644
+--- a/pos_payment_method_cashdro/static/src/js/models.esm.js
++++ b/pos_payment_method_cashdro/static/src/js/models.esm.js
+@@ -22,8 +22,8 @@ patch(PosOrder.prototype, {
+             return line;
+         }
+         if (
+-            line.payment_method &&
+-            line.payment_method.use_payment_terminal === "cashdro" &&
++            line.payment_method_id &&
++            line.payment_method_id.use_payment_terminal === "cashdro" &&
+             line.amount > 0 // For refund transactions we need to keep the amount
+         ) {
+             line.set_amount(0);
+diff --git a/pos_payment_method_cashdro/static/src/js/payment_cashdro.esm.js b/pos_payment_method_cashdro/static/src/js/payment_cashdro.esm.js
+index 0c0bdf2..2c618bf 100644
+--- a/pos_payment_method_cashdro/static/src/js/payment_cashdro.esm.js
++++ b/pos_payment_method_cashdro/static/src/js/payment_cashdro.esm.js
+@@ -107,7 +107,8 @@ export class PaymentCashdro extends PaymentInterface {
+     _cashdro_url() {
+         // Cashdro machines don't support safe POST calls, so we're sending
+         // all the data quite unsafely constantly...
+-        const method = this.pos.get_order().selected_paymentline.payment_method;
++        const order = this.pos.get_order();
++        const method = order.get_selected_paymentline()?.payment_method_id;
+         const host = method && method.cashdro_host;
+         if (!host) {
+             return false;
+-- 
+2.43.0
+