diff --git a/Makefile b/Makefile
index 63b1f0143220..9806464357e0 100644
--- a/Makefile
+++ b/Makefile
@@ -1015,9 +1015,8 @@ cmd_pad_cat = $(cmd_objcopy) && $(append) || { rm -f $@; false; }
 quiet_cmd_lzma = LZMA    $@
 cmd_lzma = lzma -c -z -k -9 $< > $@
 
-quiet_cmd_mkeficapsule = MKEFICAPSULE     $@
-cmd_mkeficapsule = $(objtree)/tools/mkeficapsule -K $(CONFIG_EFI_PKEY_FILE) \
-	-D $@
+quiet_cmd_fdtsig = FDTSIG  $@
+cmd_fdtsig = $(srctree)/tools/fdtsig.sh $(CONFIG_EFI_PKEY_FILE) $@
 
 cfg: u-boot.cfg
 
@@ -1114,7 +1113,7 @@ dtbs: dts/dt.dtb
 ifeq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE)$(CONFIG_EFI_PKEY_DTB_EMBED),yy)
 dts/dt.dtb: u-boot tools
 	$(Q)$(MAKE) $(build)=dts dtbs
-	$(call cmd,mkeficapsule)
+	$(call cmd,fdtsig)
 else
 dts/dt.dtb: u-boot
 	$(Q)$(MAKE) $(build)=dts dtbs
diff --git a/tools/Makefile b/tools/Makefile
index 02eae0286e20..71a52719620c 100644
--- a/tools/Makefile
+++ b/tools/Makefile
@@ -235,7 +235,6 @@ ifneq ($(CONFIG_EFI_CAPSULE_AUTHENTICATE),)
 HOSTLDLIBS_mkeficapsule += \
 	$(shell pkg-config --libs libssl libcrypto 2> /dev/null || echo "-lssl -lcrypto")
 endif
-mkeficapsule-objs	:= mkeficapsule.o $(LIBFDT_OBJS)
 hostprogs-$(CONFIG_EFI_HAVE_CAPSULE_SUPPORT) += mkeficapsule
 
 # We build some files with extra pedantic flags to try to minimize things
diff --git a/tools/fdtsig.sh b/tools/fdtsig.sh
new file mode 100755
index 000000000000..aaa0a9190845
--- /dev/null
+++ b/tools/fdtsig.sh
@@ -0,0 +1,40 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0+
+#
+# script to add a certificate (efi-signature-list) to dtb blob
+
+usage() {
+	if [ -n "$*" ]; then
+		echo "ERROR: $*"
+	fi
+	echo "Usage: "$(basename $0) " <esl file> <dtb file>"
+}
+
+if [ "$#" -ne 2 ]; then
+	usage "Arguments missing"
+	exit 1
+fi
+
+ESL=$1
+DTB=$2
+NEW_DTB=$(basename $DTB)_tmp
+SIG=signature
+
+cat << 'EOF' > $SIG.dts
+/dts-v1/;
+/plugin/;
+
+&{/} {
+    signature {
+	    capsule-key = /incbin/("ESL");
+    };
+};
+EOF
+
+sed -in "s/ESL/$ESL/" $SIG.dts
+
+dtc -@ -I dts -O dtb -o $SIG.dtbo $SIG.dts
+fdtoverlay -i $DTB -o $NEW_DTB -v $SIG.dtbo
+mv $NEW_DTB $DTB
+
+rm $SIG.dts $SIG.dtbo $NEW_DTB
diff --git a/tools/mkeficapsule.c b/tools/mkeficapsule.c
index 34ff1bdd82eb..97ce68ec83ee 100644
--- a/tools/mkeficapsule.c
+++ b/tools/mkeficapsule.c
@@ -4,17 +4,13 @@
  *		Author: AKASHI Takahiro
  */
 
-#include <errno.h>
 #include <getopt.h>
 #include <malloc.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 #include <linux/types.h>
-
-#include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
@@ -28,8 +24,6 @@
 #include <openssl/pkcs7.h>
 #endif
 
-#include <linux/libfdt.h>
-
 typedef __u8 u8;
 typedef __u16 u16;
 typedef __u32 u32;
@@ -39,9 +33,6 @@ typedef __s32 s32;
 
 #define aligned_u64 __aligned_u64
 
-#define SIGNATURE_NODENAME	"signature"
-#define OVERLAY_NODENAME	"__overlay__"
-
 #ifndef __packed
 #define __packed __attribute__((packed))
 #endif
@@ -59,9 +50,9 @@ efi_guid_t efi_guid_image_type_uboot_raw =
 efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
 
 #if IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE)
-static const char *opts_short = "f:r:i:I:v:D:K:P:C:m:dOh";
+static const char *opts_short = "f:r:i:I:v:P:C:m:dh";
 #else
-static const char *opts_short = "f:r:i:I:v:D:K:Oh";
+static const char *opts_short = "f:r:i:I:v:h";
 #endif
 
 static struct option options[] = {
@@ -69,15 +60,12 @@ static struct option options[] = {
 	{"raw", required_argument, NULL, 'r'},
 	{"index", required_argument, NULL, 'i'},
 	{"instance", required_argument, NULL, 'I'},
-	{"dtb", required_argument, NULL, 'D'},
-	{"public key", required_argument, NULL, 'K'},
 #if IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE)
 	{"private-key", required_argument, NULL, 'P'},
 	{"certificate", required_argument, NULL, 'C'},
 	{"monotonic-count", required_argument, NULL, 'm'},
 	{"dump-sig", no_argument, NULL, 'd'},
 #endif
-	{"overlay", no_argument, NULL, 'O'},
 	{"help", no_argument, NULL, 'h'},
 	{NULL, 0, NULL, 0},
 };
@@ -104,180 +92,6 @@ static void print_usage(void)
 	       tool_name);
 }
 
-static int fdt_add_pub_key_data(void *sptr, void *dptr, size_t key_size,
-				bool overlay)
-{
-	int parent;
-	int ov_node;
-	int frag_node;
-	int ret = 0;
-
-	if (overlay) {
-		/*
-		 * The signature would be stored in the
-		 * first fragment node of the overlay
-		 */
-		frag_node = fdt_first_subnode(dptr, 0);
-		if (frag_node == -FDT_ERR_NOTFOUND) {
-			fprintf(stderr,
-				"Couldn't find the fragment node: %s\n",
-				fdt_strerror(frag_node));
-			goto done;
-		}
-
-		ov_node = fdt_subnode_offset(dptr, frag_node, OVERLAY_NODENAME);
-		if (ov_node == -FDT_ERR_NOTFOUND) {
-			fprintf(stderr,
-				"Couldn't find the __overlay__ node: %s\n",
-				fdt_strerror(ov_node));
-			goto done;
-		}
-	} else {
-		ov_node = 0;
-	}
-
-	parent = fdt_subnode_offset(dptr, ov_node, SIGNATURE_NODENAME);
-	if (parent == -FDT_ERR_NOTFOUND) {
-		parent = fdt_add_subnode(dptr, ov_node, SIGNATURE_NODENAME);
-		if (parent < 0) {
-			ret = parent;
-			if (ret != -FDT_ERR_NOSPACE) {
-				fprintf(stderr,
-					"Couldn't create signature node: %s\n",
-					fdt_strerror(parent));
-			}
-		}
-	}
-	if (ret)
-		goto done;
-
-	/* Write the key to the FDT node */
-	ret = fdt_setprop(dptr, parent, "capsule-key",
-			  sptr, key_size);
-
-done:
-	if (ret)
-		ret = ret == -FDT_ERR_NOSPACE ? -ENOSPC : -EIO;
-
-	return ret;
-}
-
-static int add_public_key(const char *pkey_file, const char *dtb_file,
-			  bool overlay)
-{
-	int ret;
-	int srcfd = -1;
-	int destfd = -1;
-	void *sptr = NULL;
-	void *dptr = NULL;
-	off_t src_size;
-	struct stat pub_key;
-	struct stat dtb;
-
-	/* Find out the size of the public key */
-	srcfd = open(pkey_file, O_RDONLY);
-	if (srcfd == -1) {
-		fprintf(stderr, "%s: Can't open %s: %s\n",
-			__func__, pkey_file, strerror(errno));
-		ret = -1;
-		goto err;
-	}
-
-	ret = fstat(srcfd, &pub_key);
-	if (ret == -1) {
-		fprintf(stderr, "%s: Can't stat %s: %s\n",
-			__func__, pkey_file, strerror(errno));
-		ret = -1;
-		goto err;
-	}
-
-	src_size = pub_key.st_size;
-
-	/* mmap the public key esl file */
-	sptr = mmap(0, src_size, PROT_READ, MAP_SHARED, srcfd, 0);
-	if (sptr == MAP_FAILED) {
-		fprintf(stderr, "%s: Failed to mmap %s:%s\n",
-			__func__, pkey_file, strerror(errno));
-		ret = -1;
-		goto err;
-	}
-
-	/* Open the dest FDT */
-	destfd = open(dtb_file, O_RDWR);
-	if (destfd == -1) {
-		fprintf(stderr, "%s: Can't open %s: %s\n",
-			__func__, dtb_file, strerror(errno));
-		ret = -1;
-		goto err;
-	}
-
-	ret = fstat(destfd, &dtb);
-	if (ret == -1) {
-		fprintf(stderr, "%s: Can't stat %s: %s\n",
-			__func__, dtb_file, strerror(errno));
-		goto err;
-	}
-
-	dtb.st_size += src_size + 0x30;
-	if (ftruncate(destfd, dtb.st_size)) {
-		fprintf(stderr, "%s: Can't expand %s: %s\n",
-			__func__, dtb_file, strerror(errno));
-		ret = -1;
-		goto err;
-	}
-
-	errno = 0;
-	/* mmap the dtb file */
-	dptr = mmap(0, dtb.st_size, PROT_READ | PROT_WRITE, MAP_SHARED,
-		    destfd, 0);
-	if (dptr == MAP_FAILED) {
-		fprintf(stderr, "%s: Failed to mmap %s:%s\n",
-			__func__, dtb_file, strerror(errno));
-		ret = -1;
-		goto err;
-	}
-
-	if (fdt_check_header(dptr)) {
-		fprintf(stderr, "%s: Invalid FDT header\n", __func__);
-		ret = -1;
-		goto err;
-	}
-
-	ret = fdt_open_into(dptr, dptr, dtb.st_size);
-	if (ret) {
-		fprintf(stderr, "%s: Cannot expand FDT: %s\n",
-			__func__, fdt_strerror(ret));
-		ret = -1;
-		goto err;
-	}
-
-	/* Copy the esl file to the expanded FDT */
-	ret = fdt_add_pub_key_data(sptr, dptr, src_size, overlay);
-	if (ret < 0) {
-		fprintf(stderr, "%s: Unable to add public key to the FDT\n",
-			__func__);
-		ret = -1;
-		goto err;
-	}
-
-	ret = 0;
-
-err:
-	if (sptr)
-		munmap(sptr, src_size);
-
-	if (dptr)
-		munmap(dptr, dtb.st_size);
-
-	if (srcfd != -1)
-		close(srcfd);
-
-	if (destfd != -1)
-		close(destfd);
-
-	return ret;
-}
-
 struct auth_context {
 	char *key_file;
 	char *cert_file;
@@ -608,19 +422,13 @@ err_1:
 int main(int argc, char **argv)
 {
 	char *file;
-	char *pkey_file;
-	char *dtb_file;
 	efi_guid_t *guid;
 	unsigned long index, instance;
 	uint64_t mcount;
 	char *privkey_file, *cert_file;
 	int c, idx;
-	int ret;
-	bool overlay = false;
 
 	file = NULL;
-	pkey_file = NULL;
-	dtb_file = NULL;
 	guid = NULL;
 	index = 0;
 	instance = 0;
@@ -656,20 +464,6 @@ int main(int argc, char **argv)
 		case 'I':
 			instance = strtoul(optarg, NULL, 0);
 			break;
-		case 'K':
-			if (pkey_file) {
-				printf("Public Key already specified\n");
-				return -1;
-			}
-			pkey_file = optarg;
-			break;
-		case 'D':
-			if (dtb_file) {
-				printf("DTB file already specified\n");
-				return -1;
-			}
-			dtb_file = optarg;
-			break;
 #if IS_ENABLED(CONFIG_EFI_CAPSULE_AUTHENTICATE)
 		case 'P':
 			if (privkey_file) {
@@ -692,9 +486,6 @@ int main(int argc, char **argv)
 			dump_sig = 1;
 			break;
 #endif
-		case 'O':
-			overlay = true;
-			break;
 		case 'h':
 			print_usage();
 			return 0;
@@ -702,27 +493,15 @@ int main(int argc, char **argv)
 	}
 
 	/* check necessary parameters */
-	if ((file && (!(optind < argc) ||
-		      (privkey_file && !cert_file) ||
-		      (!privkey_file && cert_file))) ||
-	    ((pkey_file && !dtb_file) ||
-	     (!pkey_file && dtb_file))) {
+	if (file && (!(optind < argc) ||
+		     (privkey_file && !cert_file) ||
+		     (!privkey_file && cert_file))) {
 		print_usage();
 		exit(EXIT_FAILURE);
 	}
 
-	if (pkey_file && dtb_file) {
-		ret = add_public_key(pkey_file, dtb_file, overlay);
-		if (ret == -1) {
-			printf("Adding public key to the dtb failed\n");
-			exit(EXIT_FAILURE);
-		}
-	}
-
-	if (optind < argc &&
-	    create_fwbin(argv[optind], file, guid, index, instance,
-			 mcount, privkey_file, cert_file)
-			< 0) {
+	if (create_fwbin(argv[optind], file, guid, index, instance,
+			 mcount, privkey_file, cert_file) < 0) {
 		printf("Creating firmware capsule failed\n");
 		exit(EXIT_FAILURE);
 	}
