diff --git a/tools/firmware-utils/Makefile b/tools/firmware-utils/Makefile
index 6074ecc608d0..f4f9f233cdc2 100644
--- a/tools/firmware-utils/Makefile
+++ b/tools/firmware-utils/Makefile
@@ -30,6 +30,7 @@ define Host/Compile
 	$(call cc,buffalo-enc buffalo-lib,-Wall)
 	$(call cc,buffalo-tag buffalo-lib,-Wall)
 	$(call cc,buffalo-tftp buffalo-lib,-Wall)
+	$(call cc,cros-vbutil,-lcrypto -lpthread)
 	$(call cc,dgfirmware)
 	$(call cc,dgn3500sum,-Wall)
 	$(call cc,dns313-header,-Wall)
diff --git a/tools/firmware-utils/src/cros-vbutil.c b/tools/firmware-utils/src/cros-vbutil.c
new file mode 100644
index 000000000000..13ba9a3245b3
--- /dev/null
+++ b/tools/firmware-utils/src/cros-vbutil.c
@@ -0,0 +1,609 @@
+/*
+ * cros-vbutil - Tool for signing kernels using the Chromium OS verified boot
+ * format, using widely-shared "developer" keys. The output of this tool is
+ * intended to be written to a GPT partition of type "Chrome OS Kernel", such
+ * that a Chromium OS bootloader can find it.
+ *
+ * Much of this is adapted from Google's vboot_reference project found here:
+ *   https://chromium.googlesource.com/chromiumos/platform/vboot_reference
+ *
+ * Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *    * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *    * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *    * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Rewritten:
+ * Copyright (c) 2021 Brian Norris <computersforpeace@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <openssl/rsa.h>
+#include <openssl/x509.h>
+#include <openssl/sha.h>
+
+#define BLOCK_PAD 65536
+/* Sections are aligned to 4K blocks */
+#define ALIGN 4096
+#define ROUNDUP(x) (((x) + (ALIGN-1)) & ~(ALIGN-1))
+
+/*
+ * Signature size, in bytes. This is an RSA-2048 encryption of a SHA256 hash.
+ */
+#define SIG_SIZE (2048 / 8)
+
+/*
+ * From vboot_reference: tests/devkeys/kernel.keyblock
+ */
+static const unsigned char keyblock[] = {
+	0x43, 0x48, 0x52, 0x4f, 0x4d, 0x45, 0x4f, 0x53, 0x02, 0x00, 0x00, 0x00,
+	0x01, 0x00, 0x00, 0x00, 0xb8, 0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0xa0, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x78, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x48, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x78, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x08, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+	0x04, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
+	0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00, 0xcb, 0x02, 0x40, 0x41,
+	0x1d, 0x2d, 0x86, 0x0f, 0x6d, 0x53, 0xcc, 0xcc, 0xa7, 0x9b, 0x1b, 0xca,
+	0xdc, 0x22, 0xc4, 0xc2, 0x3a, 0x72, 0xa5, 0x12, 0x21, 0xfe, 0x78, 0x1d,
+	0x9c, 0x03, 0x65, 0x0c, 0x94, 0xba, 0x3d, 0x5b, 0x5e, 0x98, 0x16, 0x8a,
+	0xaf, 0xaf, 0x67, 0x5a, 0x46, 0x88, 0x2c, 0xf0, 0x2a, 0x65, 0xbd, 0xc7,
+	0x59, 0xcc, 0x70, 0xe9, 0x01, 0x4e, 0x7d, 0x8c, 0x43, 0x2e, 0x1c, 0x6d,
+	0x72, 0x15, 0xaf, 0xd0, 0x71, 0x9f, 0xb4, 0x3a, 0xe7, 0x44, 0x82, 0xd1,
+	0x83, 0x8b, 0x9d, 0x6c, 0x64, 0x99, 0xaf, 0xdb, 0x8a, 0xcc, 0xd1, 0xd6,
+	0x83, 0xa6, 0xa4, 0xea, 0xa9, 0x81, 0x1d, 0x9f, 0x1b, 0x5a, 0x8c, 0xf8,
+	0xdb, 0x26, 0x21, 0xb2, 0x7b, 0x53, 0x92, 0xf0, 0x6a, 0xc5, 0x8c, 0x11,
+	0xba, 0x7e, 0x43, 0xcb, 0x1e, 0x57, 0xa1, 0x6e, 0xd5, 0xfe, 0x82, 0x28,
+	0x3d, 0x6d, 0xbd, 0x97, 0xb0, 0xe8, 0xfb, 0x1f, 0x88, 0x06, 0x1b, 0x0a,
+	0xc5, 0x8f, 0x96, 0x69, 0x48, 0x69, 0x41, 0x2a, 0x52, 0xd7, 0xb7, 0x33,
+	0x78, 0x8b, 0x6f, 0x97, 0xa7, 0x7d, 0xdc, 0xd0, 0x2b, 0xd9, 0x81, 0x67,
+	0xc9, 0x3f, 0xa9, 0xb4, 0x1e, 0x0b, 0x08, 0x54, 0xc6, 0x01, 0xc6, 0x20,
+	0xe6, 0xc6, 0x09, 0x5f, 0x0a, 0xc5, 0x02, 0x05, 0x6b, 0x40, 0x96, 0x11,
+	0x20, 0xe5, 0xa2, 0x88, 0x37, 0x6a, 0xd3, 0xda, 0xda, 0xda, 0x76, 0x1c,
+	0xe4, 0x3d, 0x2c, 0xfe, 0x65, 0x86, 0x98, 0xa2, 0xa8, 0x49, 0x7d, 0x26,
+	0x45, 0x14, 0x04, 0x10, 0xe3, 0x38, 0x4b, 0x66, 0x9c, 0x5c, 0x2c, 0xe8,
+	0xd9, 0x06, 0xd4, 0xc3, 0x05, 0x94, 0x1c, 0x7b, 0x23, 0x89, 0x86, 0x1d,
+	0x32, 0xbb, 0x23, 0x90, 0x2b, 0x72, 0xd7, 0x90, 0x53, 0x52, 0x10, 0x12,
+	0xd0, 0xc2, 0xe2, 0x72, 0x81, 0x70, 0x3c, 0xb1, 0x27, 0x42, 0xec, 0xbf,
+	0x2b, 0x54, 0xd6, 0xcb, 0x61, 0xea, 0xb4, 0xd4, 0xa8, 0xde, 0xf3, 0xdf,
+	0x3d, 0xd1, 0x17, 0xde, 0x86, 0x89, 0xf4, 0xa1, 0x28, 0x5e, 0xda, 0xb4,
+	0x47, 0x19, 0x9b, 0xc2, 0xce, 0x49, 0xea, 0x63, 0xda, 0x42, 0x1c, 0x85,
+	0x1c, 0xab, 0x6c, 0xd7, 0xc2, 0xfd, 0x34, 0x1b, 0xd5, 0x11, 0xa2, 0x44,
+	0xb7, 0x7a, 0x85, 0x61, 0x03, 0xba, 0xd4, 0x64, 0xe1, 0x49, 0x87, 0x92,
+	0xe6, 0xdc, 0x39, 0x94, 0x9c, 0xba, 0xef, 0x58, 0x9e, 0x0e, 0x36, 0x98,
+	0xd7, 0xd2, 0x4c, 0x14, 0x71, 0x94, 0x78, 0xaf, 0x86, 0xe7, 0x2f, 0xe9,
+	0xf9, 0x20, 0x4d, 0xfe, 0xda, 0xd7, 0x3f, 0x89, 0xc1, 0x59, 0xae, 0xbd,
+	0x60, 0x9b, 0x97, 0xa4, 0x66, 0x00, 0xbb, 0x7b, 0xd0, 0x49, 0x85, 0x6f,
+	0x7b, 0x01, 0x24, 0xc3, 0x48, 0xe2, 0xc7, 0x61, 0x98, 0x9c, 0xe5, 0x93,
+	0x87, 0x04, 0x09, 0x3a, 0x92, 0x54, 0x1f, 0xb5, 0x80, 0x29, 0x15, 0xe5,
+	0x7f, 0xfe, 0xdc, 0xaf, 0xd3, 0xe1, 0x62, 0xc4, 0xb6, 0xdb, 0x2f, 0x1a,
+	0x08, 0xf3, 0x54, 0x06, 0x3a, 0xce, 0x5e, 0x89, 0x71, 0xdf, 0x3b, 0x5c,
+	0x8c, 0x6b, 0x83, 0xa9, 0x0c, 0x05, 0x50, 0x7b, 0x84, 0x09, 0x18, 0x66,
+	0x84, 0xe1, 0x7e, 0x60, 0xd6, 0xdc, 0xbf, 0x1c, 0xac, 0x5c, 0xdc, 0xe6,
+	0x4c, 0x9e, 0xa0, 0x4a, 0x59, 0x30, 0xff, 0x91, 0x90, 0x1e, 0x21, 0x29,
+	0x50, 0x99, 0x76, 0xfd, 0x2f, 0x5a, 0x67, 0x6a, 0x00, 0x6b, 0x40, 0x27,
+	0xe7, 0xbd, 0x17, 0xe6, 0x5f, 0x9e, 0xe4, 0x6b, 0xe0, 0x05, 0x9e, 0x7d,
+	0xcb, 0x90, 0xe9, 0x3c, 0x9c, 0x79, 0xc9, 0x47, 0xf8, 0x58, 0xbc, 0x3f,
+	0xb1, 0xa5, 0xef, 0x67, 0xf0, 0x22, 0xa1, 0x70, 0x33, 0x36, 0xb0, 0x5c,
+	0xed, 0xea, 0x4e, 0xde, 0x24, 0x0c, 0x5b, 0xd8, 0x4d, 0xbe, 0xac, 0x6a,
+	0x12, 0x31, 0xa6, 0x5e, 0x5f, 0x04, 0xb6, 0x58, 0xa1, 0xd1, 0x29, 0xa3,
+	0x33, 0x9c, 0x64, 0xb1, 0x8e, 0x3b, 0xfa, 0xaf, 0x35, 0x94, 0x7a, 0xa4,
+	0xf5, 0xcb, 0x9e, 0x67, 0x1b, 0x8d, 0x35, 0xca, 0x10, 0x69, 0x8d, 0xea,
+	0x78, 0xc2, 0xf6, 0x63, 0xc0, 0x11, 0xf1, 0xf6, 0x66, 0x70, 0x2e, 0x96,
+	0xf0, 0xbc, 0x7b, 0x1e, 0x16, 0x26, 0xde, 0xe3, 0x7f, 0xc0, 0xf4, 0x6c,
+	0x3c, 0x0b, 0x52, 0xe2, 0x07, 0xde, 0x70, 0x8b, 0xaf, 0x84, 0x95, 0x1b,
+	0x46, 0x95, 0x69, 0x05, 0x92, 0xea, 0x36, 0xa5, 0xca, 0x50, 0xdb, 0x49,
+	0xc8, 0x44, 0xee, 0x7c, 0x49, 0x40, 0x34, 0x05, 0xf3, 0x06, 0x1f, 0x1c,
+	0xcc, 0x78, 0x62, 0x1b, 0x9d, 0xe2, 0x4f, 0x3e, 0x04, 0x96, 0xba, 0xd0,
+	0xc7, 0xa2, 0x3a, 0xaa, 0xf7, 0xc3, 0xae, 0xc0, 0x6b, 0xca, 0xc8, 0x59,
+	0x90, 0xe0, 0x45, 0x7b, 0x4b, 0x60, 0xbf, 0xae, 0x15, 0x25, 0xd0, 0xa2,
+	0x2f, 0x95, 0x6a, 0x2e, 0x37, 0x24, 0x15, 0x69, 0x0e, 0x3a, 0x6d, 0x40,
+	0x21, 0xf6, 0x74, 0x5c, 0xa6, 0x9f, 0xe0, 0x03, 0x60, 0x04, 0x59, 0x70,
+	0x70, 0xa0, 0x46, 0xf4, 0xdf, 0x0a, 0x4b, 0x14, 0xab, 0x87, 0x0c, 0xaa,
+	0x64, 0x9b, 0x82, 0xca, 0x21, 0xb0, 0x72, 0xfa, 0x8b, 0x37, 0xf5, 0x60,
+	0xd7, 0xb7, 0x4e, 0x72, 0x5e, 0x13, 0x23, 0x73, 0x84, 0x6c, 0xd1, 0x8d,
+	0x72, 0xa2, 0x15, 0x8b, 0x51, 0x38, 0x90, 0x68, 0x90, 0xd9, 0x8b, 0x65,
+	0x30, 0x61, 0xdb, 0x51, 0x80, 0x58, 0xdd, 0xc3, 0xf0, 0x29, 0x33, 0xdc,
+	0x39, 0x92, 0xbf, 0x27, 0xe6, 0xc7, 0x82, 0xf6, 0xea, 0xcf, 0x21, 0xd2,
+	0xa0, 0x38, 0x02, 0x57, 0x52, 0xf5, 0xdd, 0x07, 0x99, 0xe3, 0x09, 0xd7,
+	0xad, 0x9e, 0x1e, 0xe7, 0xf3, 0x5e, 0x72, 0xa0, 0xc6, 0x9d, 0x41, 0x86,
+	0x96, 0x82, 0x74, 0x46, 0x1f, 0x05, 0xd2, 0x05, 0x25, 0x29, 0x27, 0x66,
+	0xe1, 0xab, 0x5c, 0x06, 0xf4, 0xac, 0xe7, 0xd0, 0xf8, 0xe6, 0x5e, 0x8b,
+	0x19, 0x55, 0xc2, 0x99, 0x8e, 0xa7, 0x2e, 0x66, 0x0c, 0x2a, 0x61, 0xb0,
+	0x98, 0x41, 0x93, 0x05, 0x54, 0x90, 0xaa, 0xbe, 0x15, 0x26, 0x5b, 0x77,
+	0x7c, 0xb0, 0xf8, 0x08, 0x68, 0xb6, 0xb8, 0xd4, 0xdd, 0xd8, 0xa8, 0x4f,
+	0xdd, 0xf6, 0x93, 0xe5, 0xa1, 0x88, 0x1b, 0x7a, 0x05, 0x81, 0xc5, 0x98,
+	0x34, 0x1d, 0x88, 0x63, 0x55, 0xaf, 0x9a, 0xa1, 0xcb, 0x4b, 0xaf, 0x86,
+	0xb3, 0x45, 0xda, 0xa4, 0xb4, 0xa5, 0x10, 0x7a, 0x50, 0x6a, 0xe5, 0xda,
+	0x6f, 0x8f, 0xc0, 0x1d, 0x95, 0xb1, 0x91, 0x48, 0x53, 0xc3, 0xe5, 0x1f,
+	0x0e, 0x05, 0x75, 0xaa, 0xc7, 0xd8, 0x36, 0xd0, 0x6d, 0x50, 0x48, 0xd4,
+	0xe6, 0xbd, 0xd0, 0x2d, 0x97, 0x17, 0x2d, 0xb3, 0x46, 0xab, 0x19, 0x0e,
+	0xe4, 0xac, 0xfd, 0x93, 0xab, 0x0c, 0x4c, 0xad, 0xbf, 0x58, 0x1b, 0xaa,
+	0x26, 0xcd, 0x0d, 0xda, 0xaf, 0xcb, 0xeb, 0xb0, 0x19, 0x5c, 0x46, 0x1f,
+	0x9b, 0xb0, 0xb8, 0x12, 0x6c, 0xa7, 0x4e, 0xb8, 0xa7, 0x1f, 0x12, 0x6b,
+	0xf8, 0xbe, 0x4b, 0xa9, 0x04, 0xb4, 0xf9, 0x36, 0xcc, 0xd9, 0xd5, 0x91,
+	0xac, 0x7e, 0xe9, 0x13, 0xc0, 0x7f, 0xca, 0xd7, 0xdc, 0xbe, 0xa9, 0xb0,
+	0xd6, 0x28, 0x17, 0x2f, 0xd6, 0xdf, 0x0e, 0x6b, 0x48, 0x11, 0xd6, 0x51,
+	0xc7, 0x6d, 0x87, 0xf6, 0x08, 0xb7, 0x6c, 0x69, 0xf7, 0xd6, 0x28, 0x50,
+	0x7e, 0x74, 0xad, 0x96, 0x6a, 0x0c, 0xca, 0x6b, 0xb1, 0xf1, 0xde, 0xa3,
+	0x5f, 0x23, 0xf5, 0x2a, 0x44, 0x11, 0x0f, 0xa3, 0xf7, 0x24, 0x36, 0x1b,
+	0x33, 0xe6, 0x7e, 0xd9, 0x0e, 0xa5, 0x8b, 0xa0, 0xb8, 0x8b, 0x85, 0xee,
+	0xd0, 0xe4, 0x69, 0x43, 0xc6, 0xf9, 0x5f, 0x27, 0xa5, 0xc9, 0x61, 0x3b,
+	0x8e, 0xaf, 0x62, 0x77, 0x42, 0xb6, 0x27, 0x5f, 0xed, 0x96, 0x86, 0xb3,
+	0xef, 0x32, 0x31, 0x43, 0x2e, 0x7b, 0xaf, 0x5b, 0xe2, 0x75, 0x82, 0x72,
+	0xad, 0x3b, 0x5d, 0x92, 0xc1, 0x15, 0xaa, 0xfb, 0x21, 0x07, 0xe9, 0xaa,
+	0xc4, 0xe2, 0xd7, 0x99, 0x83, 0x6c, 0x72, 0x39, 0x6f, 0x35, 0x20, 0x9d,
+	0xe0, 0xd8, 0xf8, 0xdb, 0x72, 0x24, 0xe5, 0x8d, 0x29, 0xfd, 0x24, 0x7b,
+	0xbc, 0x48, 0xe9, 0xbb, 0xc2, 0x84, 0xc7, 0xb9
+};
+static unsigned int keyblock_len = sizeof(keyblock);
+
+/*
+ * RSA 2048-bit key from vboot_reference:
+ * tests/devkeys/kernel_data_key.vbprivk, minus the 8-byte custom header.
+ */
+static const unsigned char privk[] = {
+	0x30, 0x82, 0x04, 0xa3, 0x02, 0x01, 0x00, 0x02, 0x82, 0x01, 0x01, 0x00,
+	0xcb, 0xd6, 0x54, 0x2b, 0xbf, 0xec, 0x42, 0x27, 0xb1, 0x3c, 0x70, 0x81,
+	0x72, 0xe2, 0xc2, 0xd0, 0x12, 0x10, 0x52, 0x53, 0x90, 0xd7, 0x72, 0x2b,
+	0x90, 0x23, 0xbb, 0x32, 0x1d, 0x86, 0x89, 0x23, 0x7b, 0x1c, 0x94, 0x05,
+	0xc3, 0xd4, 0x06, 0xd9, 0xe8, 0x2c, 0x5c, 0x9c, 0x66, 0x4b, 0x38, 0xe3,
+	0x10, 0x04, 0x14, 0x45, 0x26, 0x7d, 0x49, 0xa8, 0xa2, 0x98, 0x86, 0x65,
+	0xfe, 0x2c, 0x3d, 0xe4, 0x1c, 0x76, 0xda, 0xda, 0xda, 0xd3, 0x6a, 0x37,
+	0x88, 0xa2, 0xe5, 0x20, 0x11, 0x96, 0x40, 0x6b, 0x05, 0x02, 0xc5, 0x0a,
+	0x5f, 0x09, 0xc6, 0xe6, 0x20, 0xc6, 0x01, 0xc6, 0x54, 0x08, 0x0b, 0x1e,
+	0xb4, 0xa9, 0x3f, 0xc9, 0x67, 0x81, 0xd9, 0x2b, 0xd0, 0xdc, 0x7d, 0xa7,
+	0x97, 0x6f, 0x8b, 0x78, 0x33, 0xb7, 0xd7, 0x52, 0x2a, 0x41, 0x69, 0x48,
+	0x69, 0x96, 0x8f, 0xc5, 0x0a, 0x1b, 0x06, 0x88, 0x1f, 0xfb, 0xe8, 0xb0,
+	0x97, 0xbd, 0x6d, 0x3d, 0x28, 0x82, 0xfe, 0xd5, 0x6e, 0xa1, 0x57, 0x1e,
+	0xcb, 0x43, 0x7e, 0xba, 0x11, 0x8c, 0xc5, 0x6a, 0xf0, 0x92, 0x53, 0x7b,
+	0xb2, 0x21, 0x26, 0xdb, 0xf8, 0x8c, 0x5a, 0x1b, 0x9f, 0x1d, 0x81, 0xa9,
+	0xea, 0xa4, 0xa6, 0x83, 0xd6, 0xd1, 0xcc, 0x8a, 0xdb, 0xaf, 0x99, 0x64,
+	0x6c, 0x9d, 0x8b, 0x83, 0xd1, 0x82, 0x44, 0xe7, 0x3a, 0xb4, 0x9f, 0x71,
+	0xd0, 0xaf, 0x15, 0x72, 0x6d, 0x1c, 0x2e, 0x43, 0x8c, 0x7d, 0x4e, 0x01,
+	0xe9, 0x70, 0xcc, 0x59, 0xc7, 0xbd, 0x65, 0x2a, 0xf0, 0x2c, 0x88, 0x46,
+	0x5a, 0x67, 0xaf, 0xaf, 0x8a, 0x16, 0x98, 0x5e, 0x5b, 0x3d, 0xba, 0x94,
+	0x0c, 0x65, 0x03, 0x9c, 0x1d, 0x78, 0xfe, 0x21, 0x12, 0xa5, 0x72, 0x3a,
+	0xc2, 0xc4, 0x22, 0xdc, 0xca, 0x1b, 0x9b, 0xa7, 0xcc, 0xcc, 0x53, 0x6d,
+	0x0f, 0x86, 0x2d, 0x1d, 0x02, 0x03, 0x01, 0x00, 0x01, 0x02, 0x82, 0x01,
+	0x00, 0x4d, 0xb8, 0xea, 0x9d, 0x47, 0xef, 0xf1, 0x05, 0xab, 0x79, 0xed,
+	0x38, 0x1e, 0xb3, 0x42, 0x2f, 0x0e, 0x44, 0x34, 0xef, 0xf2, 0x31, 0x84,
+	0x32, 0x02, 0x22, 0xed, 0xb4, 0xdd, 0x37, 0x38, 0x41, 0x54, 0x27, 0x00,
+	0x75, 0xf6, 0x46, 0x79, 0x5a, 0x4b, 0x41, 0xe7, 0x0a, 0x27, 0xa3, 0x15,
+	0x0c, 0xd7, 0x45, 0x86, 0xe9, 0x1b, 0x14, 0xf8, 0xaa, 0x19, 0x5d, 0x69,
+	0x19, 0xa8, 0xc1, 0xfb, 0xd3, 0x67, 0xdb, 0x15, 0xf6, 0x0f, 0x2c, 0x3f,
+	0xba, 0xef, 0x19, 0x95, 0x9e, 0x15, 0xb6, 0xa1, 0xd7, 0x6c, 0xb0, 0xb2,
+	0xab, 0x12, 0xb3, 0xea, 0xa8, 0x42, 0xe4, 0xdd, 0x36, 0x5f, 0x42, 0x35,
+	0xe3, 0x3e, 0x65, 0xae, 0x91, 0xc0, 0x2a, 0xed, 0xc0, 0xdc, 0x41, 0xc6,
+	0x93, 0xc9, 0x95, 0x59, 0xab, 0xba, 0xa4, 0xa5, 0xb0, 0x89, 0xb6, 0x29,
+	0x4b, 0xd8, 0x1e, 0xf5, 0xb0, 0xde, 0xfa, 0x91, 0x11, 0x55, 0xd6, 0x9d,
+	0xe1, 0xa7, 0x9c, 0xf2, 0xf4, 0x9d, 0x7f, 0x96, 0x49, 0x7a, 0xab, 0xe9,
+	0x9a, 0x0c, 0xcb, 0x10, 0x5c, 0x67, 0xf0, 0x1d, 0xf3, 0x33, 0x84, 0xae,
+	0x6e, 0xe4, 0xbb, 0xa7, 0x57, 0x98, 0x99, 0x2b, 0xf3, 0x1d, 0xab, 0xec,
+	0x01, 0xa2, 0x2e, 0x3c, 0x10, 0x5c, 0xff, 0xe8, 0xcc, 0x50, 0x45, 0x21,
+	0x2f, 0x04, 0x69, 0xdd, 0x02, 0x5b, 0x10, 0xd6, 0x54, 0x36, 0x4c, 0x73,
+	0x0c, 0x1e, 0xc1, 0xff, 0xac, 0x60, 0x5d, 0xbc, 0x13, 0x84, 0xe8, 0xa4,
+	0xbd, 0x66, 0xca, 0xca, 0xaf, 0x55, 0x8a, 0xf8, 0x87, 0x17, 0x93, 0xbf,
+	0x66, 0xa4, 0x97, 0xe9, 0x47, 0x81, 0x03, 0xfa, 0x4c, 0x32, 0xf6, 0xec,
+	0x7a, 0x03, 0xbb, 0x2d, 0x3b, 0x9b, 0xea, 0xdc, 0x6c, 0x61, 0x7f, 0x05,
+	0xc8, 0x2d, 0x50, 0x89, 0xe9, 0x10, 0x3d, 0x3c, 0x02, 0xb0, 0x5d, 0x3e,
+	0x25, 0x71, 0xd2, 0xa1, 0xe1, 0x02, 0x81, 0x81, 0x00, 0xf6, 0x3c, 0x7f,
+	0x15, 0x63, 0x04, 0x0a, 0xd4, 0x68, 0xe8, 0xd9, 0x4b, 0x7f, 0xbc, 0xca,
+	0xb5, 0x84, 0x01, 0x71, 0x11, 0x33, 0x4d, 0xe1, 0x0a, 0xe8, 0xa7, 0x95,
+	0xcc, 0x23, 0x59, 0x19, 0xb5, 0x82, 0xaa, 0xae, 0xe4, 0x90, 0x33, 0x95,
+	0x20, 0x1a, 0xfd, 0xef, 0x8e, 0x36, 0xc1, 0x57, 0xde, 0x94, 0xdd, 0x99,
+	0x6f, 0x14, 0x0c, 0x8e, 0x30, 0xe0, 0xe7, 0x64, 0x33, 0xa7, 0x1d, 0xfd,
+	0x99, 0xdc, 0x58, 0x49, 0x4e, 0x56, 0x82, 0x43, 0xea, 0xd9, 0xf7, 0xcc,
+	0x1a, 0xf5, 0x09, 0x38, 0x4c, 0xf6, 0x87, 0x8f, 0xa6, 0x40, 0x96, 0xd1,
+	0x81, 0x62, 0xbb, 0x49, 0x53, 0x69, 0x56, 0xdf, 0x4a, 0x85, 0xfd, 0x72,
+	0x34, 0x21, 0x56, 0xa3, 0x7b, 0xda, 0x50, 0x24, 0x88, 0xc6, 0x0b, 0x03,
+	0x94, 0x0d, 0xe2, 0x03, 0x2a, 0x3c, 0x5a, 0xdd, 0x73, 0xe7, 0x07, 0x01,
+	0x7d, 0xdd, 0x38, 0x81, 0x19, 0x02, 0x81, 0x81, 0x00, 0xd3, 0xeb, 0x72,
+	0x3f, 0xf6, 0x9b, 0x03, 0x8c, 0xab, 0xd9, 0x41, 0x47, 0xbe, 0x6c, 0x07,
+	0x7f, 0xd7, 0xcb, 0xee, 0xbf, 0x45, 0x13, 0x1e, 0x53, 0x35, 0xd2, 0xe4,
+	0x6a, 0x13, 0xe9, 0xd8, 0xe3, 0xf4, 0x28, 0x5e, 0xeb, 0xd8, 0xd2, 0x87,
+	0x60, 0xdc, 0xa7, 0x21, 0xd8, 0x33, 0xce, 0xca, 0x60, 0x50, 0x1b, 0x87,
+	0xbf, 0x71, 0x88, 0x90, 0x71, 0x6f, 0xde, 0xdb, 0x33, 0x1d, 0x3c, 0xb1,
+	0x2f, 0x1b, 0x41, 0xb8, 0x55, 0xa1, 0x5c, 0xa8, 0xb2, 0x73, 0x1b, 0x39,
+	0x69, 0x5c, 0xa1, 0x57, 0x9b, 0x2e, 0xcd, 0x0d, 0x71, 0x42, 0xdf, 0x2a,
+	0xd3, 0x4f, 0x51, 0xdc, 0x35, 0x5c, 0x14, 0x86, 0x16, 0xb8, 0x22, 0x8c,
+	0x73, 0x37, 0x7a, 0x6c, 0xb7, 0xfe, 0x01, 0x1b, 0xa8, 0xc5, 0xf1, 0xff,
+	0xda, 0xd4, 0x63, 0x58, 0x81, 0xe1, 0x6a, 0xaf, 0xc2, 0x3d, 0xbb, 0x17,
+	0x3f, 0x2c, 0xf9, 0xb8, 0xa5, 0x02, 0x81, 0x81, 0x00, 0xd1, 0x1e, 0x6b,
+	0xa7, 0x54, 0x22, 0x18, 0xb8, 0x70, 0x28, 0x60, 0x72, 0x98, 0x17, 0x53,
+	0xe8, 0x78, 0x25, 0x69, 0x4a, 0xfc, 0x51, 0x45, 0xb0, 0x28, 0x0a, 0x3b,
+	0x53, 0xd5, 0x29, 0x54, 0x86, 0x2c, 0x64, 0x9c, 0x87, 0x8c, 0x57, 0xe2,
+	0x6c, 0x13, 0xc0, 0x59, 0x74, 0x63, 0xd8, 0x2b, 0xb1, 0xe2, 0xa7, 0x98,
+	0x29, 0x17, 0xd3, 0xd9, 0xe6, 0x74, 0xfa, 0xce, 0xc4, 0x77, 0x47, 0x27,
+	0x1b, 0x46, 0x60, 0xcc, 0x50, 0xf5, 0x73, 0x48, 0x0e, 0xe9, 0xf2, 0x62,
+	0xaa, 0xfa, 0x33, 0x4c, 0x57, 0x40, 0x7f, 0xbc, 0x65, 0xab, 0x30, 0xea,
+	0xd8, 0x81, 0x6b, 0x21, 0x48, 0xef, 0x8b, 0x51, 0xb3, 0x4e, 0xbc, 0x02,
+	0x03, 0x77, 0xd4, 0xc6, 0x9e, 0xe6, 0xb7, 0x6d, 0x6f, 0xa3, 0x11, 0xb3,
+	0x86, 0x47, 0x8c, 0x0c, 0xb8, 0x0f, 0xed, 0xf3, 0x68, 0xfd, 0x69, 0x9b,
+	0xc0, 0xb2, 0xe1, 0xcb, 0xf1, 0x02, 0x81, 0x80, 0x46, 0xc6, 0xdb, 0xe1,
+	0x80, 0xfb, 0x44, 0xb4, 0x36, 0xb0, 0xd8, 0x9c, 0x9d, 0x7c, 0x77, 0x04,
+	0xbb, 0x8d, 0xe0, 0xaf, 0x00, 0xe2, 0xe1, 0xbd, 0xe8, 0xbc, 0x06, 0x8d,
+	0x67, 0x19, 0x32, 0xd6, 0xef, 0x34, 0x8c, 0x7f, 0x38, 0x6b, 0x17, 0xcb,
+	0xc1, 0xe6, 0x0f, 0xe7, 0xa5, 0x65, 0xeb, 0x31, 0x3f, 0x8f, 0xf2, 0x46,
+	0x7e, 0x24, 0x9e, 0x19, 0x44, 0xc3, 0xa9, 0x71, 0xe8, 0xd1, 0xdc, 0x5b,
+	0x5f, 0x3f, 0x13, 0xd1, 0x85, 0x92, 0xec, 0xc4, 0xac, 0xac, 0xea, 0xff,
+	0xc5, 0x70, 0x1d, 0x52, 0x36, 0xcf, 0x45, 0x2e, 0x0e, 0xa7, 0x7a, 0x26,
+	0x18, 0xd7, 0xbe, 0x34, 0x14, 0x0c, 0xc6, 0xbb, 0xcf, 0xc3, 0xba, 0x24,
+	0xc0, 0xe2, 0xa2, 0x6c, 0xd0, 0xe8, 0x8d, 0xd4, 0x50, 0x48, 0x02, 0xab,
+	0x93, 0x43, 0x9a, 0xcb, 0xc5, 0xfd, 0x5b, 0xb6, 0x03, 0xe7, 0xf8, 0x5b,
+	0xa1, 0x29, 0xc6, 0x01, 0x02, 0x81, 0x80, 0x0e, 0x18, 0xbc, 0x00, 0xa3,
+	0x81, 0xda, 0xc2, 0xc8, 0xfb, 0x0a, 0xbd, 0x7f, 0xb7, 0x7f, 0xa1, 0x18,
+	0x7f, 0x49, 0xb8, 0x32, 0x83, 0x4b, 0x71, 0x35, 0x59, 0x51, 0x7b, 0xee,
+	0x8e, 0x4e, 0xd2, 0x42, 0xa8, 0x6c, 0x82, 0x57, 0xf7, 0x34, 0xf6, 0x82,
+	0x59, 0xe9, 0x75, 0x7a, 0x8f, 0x0a, 0x8d, 0x46, 0x1e, 0xa1, 0x77, 0xa1,
+	0x4c, 0xb3, 0x9e, 0x86, 0x93, 0x18, 0xdf, 0x3e, 0xfb, 0x81, 0xd0, 0xbc,
+	0x65, 0xa2, 0xb3, 0x80, 0xf0, 0x8f, 0x73, 0x2f, 0xb5, 0xc4, 0xc0, 0x03,
+	0xac, 0x24, 0xfa, 0x4f, 0x05, 0xe3, 0x16, 0x29, 0x7c, 0xff, 0x63, 0xd5,
+	0x0a, 0x0a, 0xbd, 0xd7, 0x65, 0x3a, 0xb5, 0x5e, 0xe7, 0x23, 0xfc, 0x3d,
+	0x08, 0xea, 0x62, 0xc2, 0xe3, 0x4a, 0xbb, 0x86, 0x5a, 0xc5, 0x93, 0xd7,
+	0xbc, 0xb4, 0x4c, 0xcf, 0xcf, 0x78, 0x9f, 0x52, 0x6e, 0xa1, 0x49, 0x21,
+	0xf7, 0x20, 0x42
+};
+static const unsigned int privk_len = sizeof(privk);
+
+/* Signature data (a secure hash, possibly signed) */
+struct vb2_signature {
+        /* Offset of signature data from start of this struct */
+        uint32_t sig_offset;
+        uint32_t reserved0;
+
+        /* Size of signature data in bytes */
+        uint32_t sig_size;
+        uint32_t reserved1;
+
+        /* Size of the data block which was signed in bytes */
+        uint32_t data_size;
+        uint32_t reserved2;
+} __attribute__((packed));
+
+/*
+ * Preamble block for kernel, version 2.2
+ *
+ * This should be followed by:
+ *   1) The signature data for the kernel body, pointed to by
+ *      body_signature.sig_offset.
+ *   2) The signature data for (vb2_kernel_preamble + body signature data),
+ *       pointed to by preamble_signature.sig_offset.
+ *   3) The 16-bit vmlinuz header, which is used for reconstruction of
+ *      vmlinuz image.
+ */
+struct vb2_kernel_preamble {
+	/*
+	 * Size of this preamble, including keys, signatures, vmlinuz header,
+	 * and padding, in bytes
+	 */
+	uint32_t preamble_size;
+	uint32_t reserved0;
+
+	/* Signature for this preamble (header + body signature) */
+	struct vb2_signature preamble_signature;
+
+	/* Version of this header format */
+	uint32_t header_version_major;
+	uint32_t header_version_minor;
+
+	/* Kernel version */
+	uint32_t kernel_version;
+	uint32_t reserved1;
+
+	/* Load address for kernel body */
+	uint64_t body_load_address;
+
+	/* Address of bootloader, after body is loaded at body_load_address */
+	uint64_t bootloader_address;
+
+	/* Size of bootloader in bytes */
+	uint32_t bootloader_size;
+	uint32_t reserved2;
+
+	/* Signature for the kernel body */
+	struct vb2_signature body_signature;
+
+	/* Address of 16-bit header for vmlinuz reassembly. */
+	uint64_t vmlinuz_header_address;
+
+	/* Size of 16-bit header for vmlinuz in bytes. */
+	uint32_t vmlinuz_header_size;
+	uint32_t reserved3;
+
+	uint32_t flags;
+} __attribute__((packed));
+
+/*
+ * Order matters. |data| may overlap with |siginfo|, so we need to fill out
+ * |siginfo| before computing the signature.
+ */
+static int sign(const void *data, size_t len, struct vb2_signature *siginfo,
+		void *sigout)
+{
+	unsigned char hash[SHA256_DIGEST_LENGTH];
+	SHA256_CTX sha256;
+	int ret;
+
+	memset(siginfo, 0, sizeof(*siginfo));
+	siginfo->sig_offset = (uintptr_t)(void *)sigout - (uintptr_t)(void *)siginfo;
+	siginfo->sig_size = SIG_SIZE;
+	siginfo->data_size = len;
+
+	const unsigned char *p = privk;
+	char digest_info[] = {
+		0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01,
+		0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20,
+	};
+
+	uint8_t digest[sizeof(digest_info) + sizeof(hash)];
+
+	SHA256_Init(&sha256);
+	SHA256_Update(&sha256, data, len);
+	SHA256_Final(hash, &sha256);
+
+	memcpy(digest, digest_info, sizeof(digest_info));
+	memcpy(digest + sizeof(digest_info), hash, sizeof(hash));
+
+	RSA *key = d2i_RSAPrivateKey(0, &p, privk_len);
+	if (!key) {
+		fprintf(stderr, "Failed d2i_RSAPrivateKey()\n");
+		return -1;
+	}
+
+	ret = RSA_private_encrypt(sizeof(digest), digest, sigout, key,
+				  RSA_PKCS1_PADDING);
+	if (ret == -1) {
+		fprintf(stderr, "%s: RSA_private_encrypt() failed\n", __func__);
+		return -1;
+	}
+
+	return 0;
+}
+
+static struct vb2_kernel_preamble *
+generate_preamble(const void *kblob, size_t kblob_len,
+		  size_t kernel_len, size_t config_len)
+{
+	struct vb2_kernel_preamble *h;
+	uint32_t signed_size = sizeof(struct vb2_kernel_preamble) + SIG_SIZE;
+	uint32_t block_size = signed_size + SIG_SIZE;
+	int ret;
+
+	if (block_size + keyblock_len < BLOCK_PAD)
+		block_size = BLOCK_PAD - keyblock_len;
+	h = (struct vb2_kernel_preamble *)calloc(block_size, 1);
+	if (!h) {
+		perror("calloc");
+		return NULL;
+	}
+
+	/* Sign the body, place the signature in the preamble */
+	ret = sign(kblob, kblob_len, &h->body_signature, h + 1);
+	if (ret) {
+		fprintf(stderr, "sign() failed: %d\n", ret);
+		return NULL;
+	}
+
+	h->header_version_major = 2;
+	h->header_version_minor = 2;
+	h->preamble_size = block_size;
+	h->kernel_version = 1;
+	h->body_load_address = 0x100000;
+	/*
+	 * "Bootloder" area (currently empty) is after kernel + config +
+	 * parameter page.
+	 */
+	h->bootloader_address = h->body_load_address +
+				ROUNDUP(kernel_len) +
+				ROUNDUP(config_len) +
+				ALIGN;
+	h->bootloader_size = 0x1000;
+	h->vmlinuz_header_address = 0;
+	h->vmlinuz_header_size = 0;
+	h->flags = 0;
+
+	ret = sign(h, signed_size, &h->preamble_signature,
+		   (void *)(h + 1) + SIG_SIZE);
+	if (ret) {
+		fprintf(stderr, "failed to sign preamble: %d\n", ret);
+		return NULL;
+	}
+	return h;
+}
+
+
+/*
+ * Distilled from vboot_reference futility/cmd_vbutil_kernel.c pack command.
+ *
+ * NB: "config" is the kernel cmdline
+ */
+static int vbutil_pack(const char *kernel, size_t kernel_len,
+		       const char *config, size_t config_len,
+		       void **out, size_t *out_len)
+{
+	int ret;
+	size_t kblob_len = ROUNDUP(kernel_len) + ROUNDUP(config_len) + ALIGN + ALIGN;
+	void *kblob = malloc(kblob_len);
+	if (!kblob) {
+		perror("malloc");
+		return -1;
+	}
+	void *kp = kblob;
+	memset(kblob, 0, kblob_len);
+
+	/* Kernel */
+	memcpy(kp, kernel, kernel_len);
+	kp += ROUNDUP(kernel_len);
+
+	/* Kernel command line */
+	memcpy(kp, config, config_len);
+	kp += ROUNDUP(config_len);
+
+	/* "Parameters" -- empty, 4K-aligned */
+	/* "Bootloader" region -- empty, 4K-aligned */
+	/* Vmlinuz header -- only for x86 (not currently supported), empty */
+
+	struct vb2_kernel_preamble *h;
+	h = generate_preamble(kblob, kblob_len, kernel_len, config_len);
+	if (!h) {
+		fprintf(stderr, "Failed to generate preamble\n");
+		return -1;
+	}
+	size_t outlen = sizeof(keyblock) + h->preamble_size + kblob_len;
+	void *outbuf = malloc(outlen);
+	if (!outbuf)
+		return -1;
+
+	void *p = outbuf;
+	memcpy(p, keyblock, sizeof(keyblock));
+	p += sizeof(keyblock);
+
+	memcpy(p, h, h->preamble_size);
+	p += h->preamble_size;
+
+	memcpy(p, kblob, kblob_len);
+	p += kblob_len;
+
+	if (outbuf) {
+		*out = outbuf;
+		*out_len = outlen;
+	}
+
+	return 0;
+}
+
+static void * read_file(const char *path, size_t *out_len)
+{
+	struct stat st;
+	int fd = open(path, O_RDONLY);
+	if (fd == -1) {
+		perror("failed to open");
+		return NULL;
+	}
+
+	if (fstat(fd, &st) < 0) {
+		perror("fstat");
+		return NULL;
+	}
+
+	size_t len = st.st_size;
+	void *p = malloc(len);
+	if (!p)
+		return NULL;
+
+	size_t count = 0;
+	while (count < len) {
+		ssize_t ret = read(fd, p + count, len - count);
+		if (ret < 0) {
+			perror("read");
+			return NULL;
+		}
+		count += ret;
+	}
+
+	close(fd);
+
+	*out_len = len;
+	return p;
+}
+
+int main(int argc, char * const argv[])
+{
+	int i, ret;
+	const char *kernel_file = NULL;
+	const char *out_file = NULL;
+	const char *cmdline = NULL;
+	size_t cmdline_len;
+	void *kernel;
+	size_t kernel_len;
+	void *out;
+	size_t out_len;
+
+	int opt;
+	while ((opt = getopt(argc, argv, "k:c:o:")) != -1) {
+		switch (opt) {
+		case 'k':
+			kernel_file = optarg;
+			break;
+		case 'c':
+			cmdline = optarg;
+			break;
+		case 'o':
+			out_file = optarg;
+			break;
+		default:
+			fprintf(stderr, "Usage [-k <kernel>] [-c <command line>] -o <outfile>\n");
+			return -1;
+		}
+	}
+	if (optind < argc) {
+		fprintf(stderr, "Unexpected args?\n");
+		return -1;
+	}
+	if (!out_file || !cmdline || !kernel_file) {
+		fprintf(stderr, "Missing required argument\n");
+		return -1;
+	}
+
+	/* Include the \0 terminator */
+	cmdline_len = strlen(cmdline) + 1;
+
+	kernel = read_file(kernel_file, &kernel_len);
+	if (!kernel) {
+		fprintf(stderr, "failed to read kernel file: %s\n", kernel_file);
+		return -1;
+	}
+
+	ret = vbutil_pack(kernel, kernel_len, cmdline, cmdline_len, &out, &out_len);
+	if (ret)
+		return ret;
+
+	int fd = open(out_file, O_RDWR|O_CREAT, 0644);
+	if (fd == -1) {
+		perror("open");
+		return -1;
+	}
+
+	ret = write(fd, out, out_len);
+	if (ret == -1) {
+		perror("write");
+		return -1;
+	}
+	close(fd);
+
+	return 0;
+}
