diff --git a/board/Synology/common/legacy.c b/board/Synology/common/legacy.c
new file mode 100644
index 0000000..3c89e92
--- /dev/null
+++ b/board/Synology/common/legacy.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021
+ * Walter Schweizer <swwa@users.sourceforge.net>
+ * Phil Sutter <phil@nwl.cc>
+ */
+
+#include <config.h>
+#include <vsprintf.h>
+#include <env.h>
+#include <net.h>
+#include <asm/setup.h>
+
+#include "legacy.h"
+
+static unsigned int syno_board_id(void)
+{
+	switch (CONFIG_MACH_TYPE) {
+	case 527:
+		return SYNO_DS109_ID;
+	case 3036:
+		return SYNO_AXP_4BAY_2BAY;
+	default:
+		return 0;
+	}
+}
+
+static unsigned int usb_port_modes(void)
+{
+	unsigned int i, ret = 0;
+	char var[32], *val;
+
+	for (i = 0; i < USBPORT_MAX; i++) {
+		snprintf(var, 32, "usb%dMode", i);
+		val = env_get(var);
+
+		if (!val || strcasecmp(val, "host"))
+			continue;
+
+		ret |= 1 << i;
+	}
+	return ret;
+}
+
+/* Support old kernels */
+void setup_board_tags(struct tag **in_params)
+{
+	struct tag_mv_uboot *t;
+	struct tag *params;
+	int i;
+
+	debug("Synology board tags...\n");
+
+	params = *in_params;
+	t = (struct tag_mv_uboot *)&params->u;
+
+	t->uboot_version = VER_NUM | syno_board_id();
+	t->tclk = CONFIG_SYS_TCLK;
+	t->sysclk = CONFIG_SYS_TCLK * 2;
+	t->isusbhost = usb_port_modes();
+
+	for (i = 0; i < ETHADDR_MAX; i++) {
+		char addrvar[16], mtuvar[16];
+
+		sprintf(addrvar, i ? "eth%daddr" : "ethaddr", i);
+		sprintf(mtuvar, i ? "eth%dmtu" : "ethmtu", i);
+
+		eth_env_get_enetaddr(addrvar, t->macaddr[i]);
+		t->mtu[i] = env_get_ulong(mtuvar, 10, 0);
+	}
+
+	params->hdr.tag = ATAG_MV_UBOOT;
+	params->hdr.size = tag_size(tag_mv_uboot);
+	params = tag_next(params);
+	*in_params = params;
+}