diff --git a/Makefile.am b/Makefile.am
index 21e2d0d..0ceb090 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -163,6 +163,7 @@ if BOOTLOADER
 
 if ARCH_IS_X86
 # NOTE: wdat.c is placed first so it is tried before any other drivers
+# NOTE: ipcbx21a.c must be *before* itco.c
 # NOTE: ipc4x7e_wdt.c must be *before* itco.c
 # NOTE: ipmi_wdt.c must be *before* itco.c
 efi_sources_watchdogs = \
@@ -170,6 +171,7 @@ efi_sources_watchdogs = \
 	drivers/watchdog/amdfch_wdt.c \
 	drivers/watchdog/i6300esb.c \
 	drivers/watchdog/atom-quark.c \
+	drivers/watchdog/ipcbx21a.c \
 	drivers/watchdog/ipc4x7e_wdt.c \
 	drivers/watchdog/w83627hf_wdt.c \
 	drivers/watchdog/ipmi_wdt.c \
diff --git a/drivers/watchdog/ipcbx21a.c b/drivers/watchdog/ipcbx21a.c
new file mode 100644
index 0000000..a1b8a9a
--- /dev/null
+++ b/drivers/watchdog/ipcbx21a.c
@@ -0,0 +1,76 @@
+/*
+ * EFI Boot Guard
+ *
+ * Copyright (c) Siemens AG, 2024
+ *
+ * Ported by Cedric Hombourger <cedric.hombourger@siemens.com>
+ * From unpublished code created by XingTong Wu <xingtong.wu@siemens.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.  See
+ * the COPYING file in the top-level directory.
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <efi.h>
+#include <efilib.h>
+#include <pci/header.h>
+#include <sys/io.h>
+#include "simatic.h"
+#include "utils.h"
+
+#define WDT_CTRL_REG_BX_21A			0x1854
+#define TIMEOUT_MIN_BX_21A			(1)
+#define TIMEOUT_DEF_BX_21A			(60)
+#define TIMEOUT_MAX_BX_21A			(1024)
+/* Over-Clocking WDT Timeout Value */
+#define WDT_CTRL_REG_TOV_MASK_BX_21A			(0x3FF)
+/* Over-Clocking WDT ICC Survivability Impact */
+#define WDT_CTRL_REG_ICCSURV_BIT_BX_21A			BIT(13)
+/* Over-Clocking WDT Enable */
+#define WDT_CTRL_REG_EN_BIT_BX_21A			BIT(14)
+/* Over-Clocking WDT Force All */
+#define WDT_CTRL_REG_FORCE_ALL_BIT_BX_21A		BIT(15)
+/* Over-Clocking WDT Non-ICC Survivability Mode Timeout Status */
+#define WDT_CTRL_REG_NO_ICCSURV_STS_BIT_BX_21A		BIT(24)
+/* Over-Clocking WDT ICC Survivability Mode Timeout Status */
+#define WDT_CTRL_REG_ICCSURV_STS_BIT_BX_21A		BIT(25)
+
+static EFI_STATUS init(EFI_PCI_IO __attribute__((unused)) * pci_io,
+		       UINT16 __attribute__((unused)) pci_vendor_id,
+		       UINT16 __attribute__((unused)) pci_device_id,
+		       UINTN timeout)
+{
+	UINT32 regval;
+
+	if (simatic_station_id() != SIMATIC_IPCBX_21A)
+		return EFI_UNSUPPORTED;
+
+	INFO(L"Detected SIMATIC BX-21A watchdog\n");
+
+	if (timeout < TIMEOUT_MIN_BX_21A || timeout > TIMEOUT_MAX_BX_21A) {
+		WARNING(L"Invalid timeout value (%d), default (%ds) is used.\n",
+			timeout, TIMEOUT_DEF_BX_21A);
+		timeout = TIMEOUT_DEF_BX_21A;
+	}
+
+	regval = inl(WDT_CTRL_REG_BX_21A);
+	/* setup timeout value */
+	regval &= (~WDT_CTRL_REG_TOV_MASK_BX_21A);
+	regval |= (timeout - 1);
+	/* get and clear status */
+	regval |= WDT_CTRL_REG_NO_ICCSURV_STS_BIT_BX_21A;
+	regval |= WDT_CTRL_REG_ICCSURV_STS_BIT_BX_21A;
+	outl(regval, WDT_CTRL_REG_BX_21A);
+
+	/* start watchdog */
+	regval = inl(WDT_CTRL_REG_BX_21A);
+	regval |= (WDT_CTRL_REG_EN_BIT_BX_21A |
+			WDT_CTRL_REG_ICCSURV_BIT_BX_21A |
+			WDT_CTRL_REG_FORCE_ALL_BIT_BX_21A);
+	outl(regval, WDT_CTRL_REG_BX_21A);
+
+	return EFI_SUCCESS;
+}
+
+WATCHDOG_REGISTER(init);
diff --git a/include/simatic.h b/include/simatic.h
index 6685045..eed82da 100644
--- a/include/simatic.h
+++ b/include/simatic.h
@@ -25,6 +25,7 @@
 
 #define SIMATIC_IPC427E				0x0a01
 #define SIMATIC_IPC477E				0x0a02
+#define SIMATIC_IPCBX_21A			0x1101
 #define SIMATIC_IPCBX_56A			0x1201
 #define SIMATIC_IPCBX_59A			0x1202