diff --git a/plat/allwinner/common/include/sunxi_private.h b/plat/allwinner/common/include/sunxi_private.h
index b68d23f..6cf4670 100644
--- a/plat/allwinner/common/include/sunxi_private.h
+++ b/plat/allwinner/common/include/sunxi_private.h
@@ -41,4 +41,12 @@
 int sunxi_init_platform_r_twi(uint16_t socid, bool use_rsb);
 void sunxi_execute_arisc_code(uint32_t *code, size_t size, uint16_t param);
 
+#ifdef SUNXI_BL31_IN_DRAM
+void sunxi_prepare_dtb(void *fdt);
+#else
+static inline void sunxi_prepare_dtb(void *fdt)
+{
+}
+#endif
+
 #endif /* SUNXI_PRIVATE_H */
diff --git a/plat/allwinner/common/sunxi_bl31_setup.c b/plat/allwinner/common/sunxi_bl31_setup.c
index d3c4507..72bfbd9 100644
--- a/plat/allwinner/common/sunxi_bl31_setup.c
+++ b/plat/allwinner/common/sunxi_bl31_setup.c
@@ -13,6 +13,8 @@
 #include <arch.h>
 #include <arch_helpers.h>
 #include <common/debug.h>
+#include <common/fdt_fixup.h>
+#include <common/fdt_wrappers.h>
 #include <drivers/arm/gicv2.h>
 #include <drivers/console.h>
 #include <drivers/generic_delay_timer.h>
@@ -175,6 +177,8 @@
 
 	sunxi_pmic_setup(soc_id, fdt);
 
+	sunxi_prepare_dtb(fdt);
+
 	INFO("BL31: Platform setup done\n");
 }
 
diff --git a/plat/allwinner/common/sunxi_common.c b/plat/allwinner/common/sunxi_common.c
index 27321cc..d47d360 100644
--- a/plat/allwinner/common/sunxi_common.c
+++ b/plat/allwinner/common/sunxi_common.c
@@ -26,7 +26,7 @@
 	MAP_REGION(SUNXI_DRAM_BASE, SUNXI_DRAM_VIRT_BASE, SUNXI_DRAM_SEC_SIZE,
 		   MT_RW_DATA | MT_SECURE),
 	MAP_REGION(PRELOADED_BL33_BASE, SUNXI_BL33_VIRT_BASE,
-		   SUNXI_DRAM_MAP_SIZE, MT_RO_DATA | MT_NS),
+		   SUNXI_DRAM_MAP_SIZE, MT_RW_DATA | MT_NS),
 	{},
 };
 
diff --git a/plat/allwinner/sun50i_h616/platform.mk b/plat/allwinner/sun50i_h616/platform.mk
index 1003aab..fc09af7 100644
--- a/plat/allwinner/sun50i_h616/platform.mk
+++ b/plat/allwinner/sun50i_h616/platform.mk
@@ -17,6 +17,8 @@
 endif
 
 BL31_SOURCES		+=	drivers/allwinner/axp/axp805.c		\
-				drivers/allwinner/sunxi_rsb.c
+				drivers/allwinner/sunxi_rsb.c		\
+				common/fdt_fixup.c			\
+				${AW_PLAT}/${PLAT}/prepare_dtb.c
 
 $(eval $(call add_define,SUNXI_BL31_IN_DRAM))
diff --git a/plat/allwinner/sun50i_h616/prepare_dtb.c b/plat/allwinner/sun50i_h616/prepare_dtb.c
new file mode 100644
index 0000000..e94b0b4
--- /dev/null
+++ b/plat/allwinner/sun50i_h616/prepare_dtb.c
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2021, ARM Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <libfdt.h>
+
+#include <common/debug.h>
+#include <common/fdt_fixup.h>
+#include <common/fdt_wrappers.h>
+
+#include <sunxi_private.h>
+
+void sunxi_prepare_dtb(void *fdt)
+{
+	int ret;
+
+	if (fdt == NULL || fdt_check_header(fdt) != 0) {
+		return;
+	}
+	ret = fdt_open_into(fdt, fdt, 0x100000);
+	if (ret < 0) {
+		ERROR("Preparing devicetree at %p: error %d\n", fdt, ret);
+		return;
+	}
+
+	/* Reserve memory used by Trusted Firmware. */
+	if (fdt_add_reserved_memory(fdt, "tf-a@40000000", BL31_BASE,
+				    BL31_LIMIT - BL31_BASE)) {
+		WARN("Failed to add reserved memory nodes to DT.\n");
+		return;
+	}
+
+	ret = fdt_pack(fdt);
+	if (ret < 0) {
+		ERROR("Failed to pack devicetree at %p: error %d\n",
+		      fdt, ret);
+	} else {
+		clean_dcache_range((uintptr_t)fdt, fdt_blob_size(fdt));
+		INFO("Changed devicetree to reserve BL31 memory.\n");
+	}
+}