diff --git a/common/utility_stub.c b/common/utility_stub.c
index 8d21897..2d01226 100644
--- a/common/utility_stub.c
+++ b/common/utility_stub.c
@@ -47,9 +47,12 @@
   return match;
 }
 
-void* StatefulMemcpy(MemcpyState* state, void* dst, int len) {
+void* StatefulMemcpy(MemcpyState* state, void* dst,
+                     uint64_t len) {
+  if (state->overrun)
+    return NULL;
   if (len > state->remaining_len) {
-    state->remaining_len = -1;
+    state->overrun = 1;
     return NULL;
   }
   Memcpy(dst, state->remaining_buf, len);
@@ -58,9 +61,12 @@
   return dst;
 }
 
-const void* StatefulMemcpy_r(MemcpyState* state, const void* src, int len) {
+const void* StatefulMemcpy_r(MemcpyState* state, const void* src,
+                             uint64_t len) {
+  if (state->overrun)
+    return NULL;
   if (len > state->remaining_len) {
-    state->remaining_len = -1;
+    state->overrun = 1;
     return NULL;
   }
   Memcpy(state->remaining_buf, src, len);
diff --git a/crypto/rsa_utility.c b/crypto/rsa_utility.c
index 3559dfd..5ac2db4 100644
--- a/crypto/rsa_utility.c
+++ b/crypto/rsa_utility.c
@@ -42,6 +42,8 @@
 
   st.remaining_buf = (uint8_t*) buf;
   st.remaining_len = len;
+  st.overrun = 0;
+
   StatefulMemcpy(&st, &key->len, sizeof(key->len));
   key_len = key->len * sizeof(uint32_t);  /* key length in bytes. */
 
@@ -60,7 +62,7 @@
   StatefulMemcpy(&st, &key->n0inv, sizeof(key->n0inv));
   StatefulMemcpy(&st, key->n, key_len);
   StatefulMemcpy(&st, key->rr, key_len);
-  if (st.remaining_len != 0) {  /* Underrun or overrun. */
+  if (st.overrun || st.remaining_len != 0) {  /* Underrun or overrun. */
     RSAPublicKeyFree(key);
     return NULL;
   }
@@ -71,7 +73,7 @@
 int RSAVerifyBinary_f(const uint8_t* key_blob,
                       const RSAPublicKey* key,
                       const uint8_t* buf,
-                      int len,
+                      uint64_t len,
                       const uint8_t* sig,
                       int algorithm) {
   RSAPublicKey* verification_key = NULL;
diff --git a/include/firmware_image.h b/include/firmware_image.h
index 778669b..810e3a0 100644
--- a/include/firmware_image.h
+++ b/include/firmware_image.h
@@ -141,7 +141,7 @@
 int VerifyFirmwarePreamble(RSAPublicKey* sign_key,
                            const uint8_t* preamble_blob,
                            int algorithm,
-                           int* firmware_len);
+                           uint64_t* firmware_len);
 
 /* Checks the signature on the preamble + firmware data at
  * [preamble_start] and [firmware_data_start].
@@ -155,7 +155,7 @@
 int VerifyFirmwareData(RSAPublicKey* sign_key,
                        const uint8_t* preamble_start,
                        const uint8_t* firmware_data_start,
-                       int firmware_len,
+                       uint64_t firmware_len,
                        int algorithm);
 
 /* Performs a chained verify of the firmware blob [firmware_blob].
diff --git a/include/kernel_image.h b/include/kernel_image.h
index f8bddff..3718624 100644
--- a/include/kernel_image.h
+++ b/include/kernel_image.h
@@ -163,7 +163,7 @@
 int VerifyKernelConfig(RSAPublicKey* kernel_sign_key,
                        const uint8_t* kernel_config_blob,
                        int algorithm,
-                       int* kernel_len);
+                       uint64_t* kernel_len);
 
 /* Checks the signature on the kernel data at location [kernel_data_start].
  * The length of the actual kernel data is kernel _len and it is assumed to
@@ -175,7 +175,7 @@
 int VerifyKernelData(RSAPublicKey* kernel_sign_key,
                      const uint8_t* kernel_config_start,
                      const uint8_t* kernel_data_start,
-                     int kernel_len,
+                     uint64_t kernel_len,
                      int algorithm);
 
 /* Performs a chained verify of the kernel blob [kernel_blob]. If
diff --git a/include/rsa_utility.h b/include/rsa_utility.h
index d3c3e5c..652227c 100644
--- a/include/rsa_utility.h
+++ b/include/rsa_utility.h
@@ -44,7 +44,7 @@
 int RSAVerifyBinary_f(const uint8_t* key_blob,
                       const RSAPublicKey* key,
                       const uint8_t* buf,
-                      int len,
+                      uint64_t len,
                       const uint8_t* sig,
                       int algorithm);
 
diff --git a/include/utility.h b/include/utility.h
index 7971347..429223c 100644
--- a/include/utility.h
+++ b/include/utility.h
@@ -44,7 +44,8 @@
 /* Track remaining data to be read in a buffer. */
 typedef struct MemcpyState {
   void* remaining_buf;
-  uint64_t remaining_len;
+  uint64_t remaining_len;  /* Remaining length of the buffer. */
+  uint8_t overrun;  /* Flag set to 1 when an overrun occurs. */
 } MemcpyState;
 
 /* Copy [len] bytes into [dst] only if there's enough data to read according
@@ -55,7 +56,7 @@
  * Useful for iterating through a binary blob to populate a struct. After the
  * first failure (buffer overrun), successive calls will always fail.
  */
-void* StatefulMemcpy(MemcpyState* state, void* dst, int len);
+void* StatefulMemcpy(MemcpyState* state, void* dst, uint64_t len);
 
 /* Like StatefulMemcpy() but copies in the opposite direction, populating
  * data from [src] into the buffer encapsulated in state [state].
@@ -65,6 +66,6 @@
  * Useful for iterating through a structure to populate a binary blob. After the
  * first failure (buffer overrun), successive calls will always fail.
  */
-const void* StatefulMemcpy_r(MemcpyState* state, const void* src, int len);
+const void* StatefulMemcpy_r(MemcpyState* state, const void* src, uint64_t len);
 
 #endif  /* VBOOT_REFERENCE_UTILITY_H_ */
diff --git a/tests/Makefile b/tests/Makefile
index 585327a..3645e7d 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -12,7 +12,9 @@
 UTIL_LIBS = $(TOP)/utils/file_keys.o $(TOP)/utils/signature_digest.o
 LIBS = $(IMAGE_LIBS) $(UTIL_LIBS) -lcrypto $(BASE_LIBS)
 
-tests: firmware_image_tests \
+tests: big_firmware_tests \
+	big_kernel_tests \
+	firmware_image_tests \
 	firmware_rollback_tests \
 	firmware_splicing_tests \
 	firmware_verify_benchmark \
@@ -27,6 +29,12 @@
 	verify_firmware_fuzz_driver \
 	verify_kernel_fuzz_driver
 
+big_firmware_tests: big_firmware_tests.c rollback_index_mock.c test_common.c
+	$(CC) $(CFLAGS) $(INCLUDES) $^ -o $@ $(LIBS)
+
+big_kernel_tests: big_kernel_tests.c rollback_index_mock.c test_common.c
+	$(CC) $(CFLAGS) $(INCLUDES) $^ -o $@ $(LIBS)
+
 firmware_image_tests: firmware_image_tests.c rollback_index_mock.c test_common.c
 	$(CC) $(CFLAGS) $(INCLUDES) $^ -o $@ $(LIBS)
 
@@ -79,7 +87,9 @@
 	$(CC) $(CFLAGS) $(INCLUDES) $^ -o $@ $(LIBS)
 
 clean:
-	rm -f firmware_image_tests \
+	rm -f big_firmware_tests \
+		big_kernel_tests \
+		firmware_image_tests \
 		firmware_rollback_tests \
 		firmware_splicing_tests \
 		firmware_verify_benchmark \
diff --git a/tests/big_firmware_tests.c b/tests/big_firmware_tests.c
new file mode 100644
index 0000000..4079add
--- /dev/null
+++ b/tests/big_firmware_tests.c
@@ -0,0 +1,74 @@
+/* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Tests if firmware image library deals with very large firmware. This
+ * is a quick and dirty test for detecting integer overflow issues.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "file_keys.h"
+#include "firmware_image.h"
+#include "rsa_utility.h"
+#include "test_common.h"
+#include "utility.h"
+
+/* Choose a firmware size greater than the range of 32-bits unsigned. */
+#define BIG_FIRMWARE_SIZE ((uint64_t) 0x100000000)
+
+#define ROOT_KEY_BASE_NAME "testkeys/key_rsa8192"
+#define FIRMWARE_KEY_BASE_NAME "testkeys/key_rsa1024"
+
+const char* kRootKeyPublicFile = ROOT_KEY_BASE_NAME ".keyb";
+const char* kRootKeyFile = ROOT_KEY_BASE_NAME ".pem";
+const char* kFirmwareKeyPublicFile = FIRMWARE_KEY_BASE_NAME ".keyb";
+const char* kFirmwareKeyFile = FIRMWARE_KEY_BASE_NAME ".pem";
+
+int BigFirmwareTest(void) {
+  int error_code = 0;
+  uint64_t len;
+  uint8_t* firmware_blob = NULL;
+  RSAPublicKey* root_key = RSAPublicKeyFromFile(kRootKeyPublicFile);
+  uint8_t* root_key_blob = BufferFromFile(kRootKeyPublicFile, &len);
+  uint8_t* firmware_sign_key_buf= BufferFromFile(kFirmwareKeyPublicFile, &len);
+  fprintf(stderr, "Generating Big FirmwareImage...");
+  FirmwareImage* image =
+      GenerateTestFirmwareImage(0, /* RSA1024/SHA1 */
+                                firmware_sign_key_buf,
+                                1,  /* Firmware Key Version. */
+                                1,  /* Firmware Version */
+                                BIG_FIRMWARE_SIZE,
+                                kRootKeyFile,
+                                kFirmwareKeyFile,
+                                'F');  /* Firmware data fill. */
+  if (!root_key || !root_key_blob || !firmware_sign_key_buf || !image) {
+    error_code = 1;
+    goto cleanup;
+  }
+  fprintf(stderr, "Done.\n");
+  TEST_EQ(VerifyFirmwareImage(root_key, image),
+          VERIFY_FIRMWARE_SUCCESS,
+          "Big FirmwareImage Verification");
+  firmware_blob = GetFirmwareBlob(image, &len);
+  TEST_EQ(VerifyFirmware(root_key_blob, firmware_blob),
+          VERIFY_FIRMWARE_SUCCESS,
+          "Big Firmware Blob Verification");
+
+ cleanup:
+  Free(firmware_blob);
+  FirmwareImageFree(image);
+  Free(firmware_sign_key_buf);
+  RSAPublicKeyFree(root_key);
+  return error_code;
+}
+
+int main(int argc, char* argv[1])
+{
+  int error_code = 0;
+  error_code = BigFirmwareTest();
+  if (!gTestSuccess)
+    error_code = 255;
+  return error_code;
+}
diff --git a/tests/big_kernel_tests.c b/tests/big_kernel_tests.c
new file mode 100644
index 0000000..81943ba
--- /dev/null
+++ b/tests/big_kernel_tests.c
@@ -0,0 +1,76 @@
+/* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ * Tests if firmware image library deals with very large firmware. This
+ * is a quick and dirty test for detecting integer overflow issues.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "file_keys.h"
+#include "kernel_image.h"
+#include "rsa_utility.h"
+#include "test_common.h"
+#include "utility.h"
+
+/* Choose a kernel size greater than the range of 32-bits unsigned. */
+#define BIG_KERNEL_SIZE ((uint64_t) 0x100000000)
+
+#define FIRMWARE_KEY_BASE_NAME "testkeys/key_rsa2048"
+#define KERNEL_KEY_BASE_NAME "testkeys/key_rsa1024"
+
+const char* kFirmwareKeyPublicFile = FIRMWARE_KEY_BASE_NAME ".keyb";
+const char* kFirmwareKeyFile = FIRMWARE_KEY_BASE_NAME ".pem";
+const char* kKernelKeyPublicFile = KERNEL_KEY_BASE_NAME ".keyb";
+const char* kKernelKeyFile = KERNEL_KEY_BASE_NAME ".pem";
+
+int BigKernelTest() {
+  int error_code = 0;
+  uint64_t len;
+  uint8_t* kernel_blob = NULL;
+  RSAPublicKey* firmware_key = RSAPublicKeyFromFile(kFirmwareKeyPublicFile);
+  uint8_t* firmware_key_blob = BufferFromFile(kFirmwareKeyPublicFile, &len);
+  uint8_t* kernel_sign_key_buf = BufferFromFile(kKernelKeyPublicFile, &len);
+  fprintf(stderr, "Generating Big KernelImage...");
+  KernelImage* image =
+      GenerateTestKernelImage(3,  /* RSA2048/SHA1 */
+                              0,  /* RSA1024/SHA1 */
+                              kernel_sign_key_buf,
+                              1,  /* Kernel Key Version. */
+                              1,  /* Kernel Version */
+                              BIG_KERNEL_SIZE,
+                              kFirmwareKeyFile,
+                              kKernelKeyFile,
+                              'K');  /* Kernel Data Fill. */
+  if (!firmware_key || !firmware_key_blob || !kernel_sign_key_buf || !image) {
+    error_code = 1;
+    goto cleanup;
+  }
+  fprintf(stderr, "Done.\n");
+  TEST_EQ(VerifyKernelImage(firmware_key, image, 0),
+          VERIFY_FIRMWARE_SUCCESS,
+          "Big KernelImage Verification");
+  kernel_blob = GetKernelBlob(image, &len);
+  TEST_EQ(VerifyKernel(firmware_key_blob, kernel_blob, 0),
+          VERIFY_FIRMWARE_SUCCESS,
+          "Big Kernel Blob Verification");
+
+cleanup:
+  Free(kernel_blob);
+  KernelImageFree(image);
+  Free(kernel_sign_key_buf);
+  Free(firmware_key_blob);
+  RSAPublicKeyFree(firmware_key);
+  return error_code;
+}
+
+int main(int argc, char* argv[1])
+{
+  int error_code = 0;
+  error_code = BigKernelTest();
+  if (!gTestSuccess)
+    error_code = 255;
+  return error_code;
+}
diff --git a/tests/firmware_rollback_tests.c b/tests/firmware_rollback_tests.c
index e36c003..9973ec7 100644
--- a/tests/firmware_rollback_tests.c
+++ b/tests/firmware_rollback_tests.c
@@ -15,6 +15,8 @@
 #include "rollback_index.h"
 #include "test_common.h"
 
+const char* kRootKeyPublicFile = "testkeys/key_rsa8192.keyb";
+
 /* Tests that check for correctness of the VerifyFirmwareDriver_f() logic
  * and rollback prevention. */
 void VerifyFirmwareDriverTest(void) {
@@ -23,8 +25,7 @@
   uint8_t* corrupt_firmwareA = NULL;
   uint8_t* corrupt_firmwareB = NULL;
   uint64_t len;
-  uint8_t* root_key_pub = BufferFromFile("testkeys/key_rsa8192.keyb",
-                                         &len);
+  uint8_t* root_key_pub = BufferFromFile(kRootKeyPublicFile, &len);
 
   /* Initialize rollback index state. */
   g_firmware_key_version = 1;
diff --git a/tests/firmware_splicing_tests.c b/tests/firmware_splicing_tests.c
index 519e2a1..c71b8b4 100644
--- a/tests/firmware_splicing_tests.c
+++ b/tests/firmware_splicing_tests.c
@@ -15,6 +15,14 @@
 #include "test_common.h"
 #include "utility.h"
 
+#define ROOT_KEY_BASE_NAME "testkeys/key_rsa8192"
+#define FIRMWARE_KEY_BASE_NAME "testkeys/key_rsa1024"
+
+const char* kRootKeyPublicFile = ROOT_KEY_BASE_NAME ".keyb";
+const char* kRootKeyFile = ROOT_KEY_BASE_NAME ".pem";
+const char* kFirmwareKeyPublicFile = FIRMWARE_KEY_BASE_NAME ".keyb";
+const char* kFirmwareKeyFile = FIRMWARE_KEY_BASE_NAME ".pem";
+
 void VerifyFirmwareSplicingTest()
 {
   uint64_t len;
@@ -22,26 +30,25 @@
   FirmwareImage* image2 = NULL;
   uint8_t* firmware_blob = NULL;
   uint8_t* firmware_sign_key_buf = NULL;
-  RSAPublicKey* root_key = RSAPublicKeyFromFile("testkeys/key_rsa8192.keyb");
-  uint8_t* root_key_blob = BufferFromFile("testkeys/key_rsa8192.keyb",
-                                          &len);
-  firmware_sign_key_buf= BufferFromFile("testkeys/key_rsa1024.keyb", &len);
+  RSAPublicKey* root_key = RSAPublicKeyFromFile(kRootKeyPublicFile);
+  uint8_t* root_key_blob = BufferFromFile(kRootKeyPublicFile, &len);
+  firmware_sign_key_buf= BufferFromFile(kFirmwareKeyPublicFile, &len);
   image1 = GenerateTestFirmwareImage(0, /* RSA1024/SHA1 */
                                      firmware_sign_key_buf,
                                      1,  /* Firmware Key Version. */
                                      1,  /* Firmware Version */
                                      1000,
-                                     "testkeys/key_rsa8192.pem",
-                                     "testkeys/key_rsa1024.pem",
-                                     (uint8_t) 'F');  /* Firmware data fill. */
+                                     kRootKeyFile,
+                                     kFirmwareKeyFile,
+                                     'F');  /* Firmware data fill. */
   image2 = GenerateTestFirmwareImage(0, /* RSA1024/SHA1 */
                                      firmware_sign_key_buf,
                                      1,  /* Firmware Key Version. */
                                      2,  /* Firmware Version */
                                      1000,
-                                     "testkeys/key_rsa8192.pem",
-                                     "testkeys/key_rsa1024.pem",
-                                     (uint8_t) 'G');  /* Firmware data fill. */
+                                     kRootKeyFile,
+                                     kFirmwareKeyFile,
+                                     'G');  /* Different Firmware data fill. */
   /* Verify that the originals verify. */
   TEST_EQ(VerifyFirmwareImage(root_key, image1),
           VERIFY_FIRMWARE_SUCCESS,
diff --git a/tests/kernel_rollback_tests.c b/tests/kernel_rollback_tests.c
index c956300..eafbaaa 100644
--- a/tests/kernel_rollback_tests.c
+++ b/tests/kernel_rollback_tests.c
@@ -15,12 +15,14 @@
 #include "test_common.h"
 #include "utility.h"
 
+const char* kFirmwareKeyPublicFile = "testkeys/key_rsa1024.keyb";
+
 /* Tests that check for correctness of the VerifyFirmwareDriver_f() logic
  * and rollback prevention. */
 void VerifyKernelDriverTest(void) {
   uint64_t len;
-  uint8_t* firmware_key_pub = BufferFromFile("testkeys/key_rsa1024.keyb",
-                                             &len);
+  uint8_t* firmware_key_pub = BufferFromFile(kFirmwareKeyPublicFile, &len);
+
   /* Initialize kernel blobs, including their associated parition
    * table attributed. */
   kernel_entry valid_kernelA =  {
diff --git a/tests/kernel_splicing_tests.c b/tests/kernel_splicing_tests.c
index bdd3101..da29eb1 100644
--- a/tests/kernel_splicing_tests.c
+++ b/tests/kernel_splicing_tests.c
@@ -15,6 +15,14 @@
 #include "test_common.h"
 #include "utility.h"
 
+#define FIRMWARE_KEY_BASE_NAME "testkeys/key_rsa2048"
+#define KERNEL_KEY_BASE_NAME "testkeys/key_rsa1024"
+
+const char* kFirmwareKeyPublicFile = FIRMWARE_KEY_BASE_NAME ".keyb";
+const char* kFirmwareKeyFile = FIRMWARE_KEY_BASE_NAME ".pem";
+const char* kKernelKeyPublicFile = KERNEL_KEY_BASE_NAME ".keyb";
+const char* kKernelKeyFile = KERNEL_KEY_BASE_NAME ".pem";
+
 void VerifyKernelSplicingTest()
 {
   uint64_t len;
@@ -22,29 +30,27 @@
   KernelImage* image2 = NULL;
   uint8_t* kernel_blob = NULL;
   uint8_t* kernel_sign_key_buf = NULL;
-  RSAPublicKey* firmware_key =
-      RSAPublicKeyFromFile("testkeys/key_rsa2048.keyb");
-  uint8_t* firmware_key_blob = BufferFromFile("testkeys/key_rsa2048.keyb",
-                                              &len);
-  kernel_sign_key_buf= BufferFromFile("testkeys/key_rsa1024.keyb", &len);
+  RSAPublicKey* firmware_key = RSAPublicKeyFromFile(kFirmwareKeyPublicFile);
+  uint8_t* firmware_key_blob = BufferFromFile(kFirmwareKeyPublicFile, &len);
+  kernel_sign_key_buf= BufferFromFile(kKernelKeyPublicFile, &len);
   image1 = GenerateTestKernelImage(3, /* RSA2048/SHA1 */
                                    0, /* RSA1024/SHA1 */
                                    kernel_sign_key_buf,
                                    1,  /* Kernel Key Version. */
                                    1,  /* Kernel Version */
                                    1000,  /* Kernel Size. */
-                                   "testkeys/key_rsa2048.pem",
-                                   "testkeys/key_rsa1024.pem",
-                                   (uint8_t) 'K');  /* Kernel data fill. */
+                                   kFirmwareKeyFile,
+                                   kKernelKeyFile,
+                                   'K');  /* Kernel data fill. */
   image2 = GenerateTestKernelImage(3,  /* RSA2058/SHA1 */
                                    0, /* RSA1024/SHA1 */
                                    kernel_sign_key_buf,
                                    1,  /* Kernel Key Version. */
                                    2,  /* Kernel Version */
                                    1000,  /* Kernel Size */
-                                   "testkeys/key_rsa2048.pem",
-                                   "testkeys/key_rsa1024.pem",
-                                   (uint8_t) 'K');  /* Kernel data fill. */
+                                   kFirmwareKeyFile,
+                                   kKernelKeyFile,
+                                   'L');  /* Different Kernel data fill. */
   /* Make sure the originals verify. */
   TEST_EQ(VerifyKernelImage(firmware_key, image1, 0),
           VERIFY_KERNEL_SUCCESS,
diff --git a/tests/test_common.c b/tests/test_common.c
index 929e91f..b57f6ed 100644
--- a/tests/test_common.c
+++ b/tests/test_common.c
@@ -37,7 +37,7 @@
                                          const uint8_t* firmware_sign_key,
                                          int firmware_key_version,
                                          int firmware_version,
-                                         int firmware_len,
+                                         uint64_t firmware_len,
                                          const char* root_key_file,
                                          const char* firmware_key_file,
                                          uint8_t firmware_data_fill_char) {
@@ -84,7 +84,7 @@
                                   const uint8_t* firmware_sign_key,
                                   int firmware_key_version,
                                   int firmware_version,
-                                  int firmware_len,
+                                  uint64_t firmware_len,
                                   const char* root_key_file,
                                   const char* firmware_key_file) {
   FirmwareImage* image = NULL;
@@ -142,7 +142,7 @@
                                      const uint8_t* kernel_sign_key,
                                      int kernel_key_version,
                                      int kernel_version,
-                                     int kernel_len,
+                                     uint64_t kernel_len,
                                      const char* firmware_key_file,
                                      const char* kernel_key_file,
                                      uint8_t kernel_data_fill_char) {
@@ -197,7 +197,7 @@
                                 const uint8_t* kernel_sign_key,
                                 int kernel_key_version,
                                 int kernel_version,
-                                int kernel_len,
+                                uint64_t kernel_len,
                                 const char* firmware_key_file,
                                 const char* kernel_key_file) {
   KernelImage* image = NULL;
diff --git a/tests/test_common.h b/tests/test_common.h
index 15746b5..6fed1b4 100644
--- a/tests/test_common.h
+++ b/tests/test_common.h
@@ -22,7 +22,7 @@
                                          const uint8_t* firmware_sign_key,
                                          int firmware_key_version,
                                          int firmware_version,
-                                         int firmware_len,
+                                         uint64_t firmware_len,
                                          const char* root_key_file,
                                          const char* firmware_key_file,
                                          uint8_t firmware_data_fill_char);
@@ -30,7 +30,7 @@
                                   const uint8_t* firmware_sign_key,
                                   int firmware_key_version,
                                   int firmware_version,
-                                  int firmware_len,
+                                  uint64_t firmware_len,
                                   const char* root_key_file,
                                   const char* firmware_key_file);
 
@@ -40,7 +40,7 @@
                                      const uint8_t* kernel_sign_key,
                                      int kernel_key_version,
                                      int kernel_version,
-                                     int kernel_len,
+                                     uint64_t kernel_len,
                                      const char* firmware_key_file,
                                      const char* kernel_key_file,
                                      uint8_t kernel_data_fill_char);
@@ -50,7 +50,7 @@
                                 const uint8_t* kernel_sign_key,
                                 int kernel_key_version,
                                 int kernel_version,
-                                int kernel_len,
+                                uint64_t kernel_len,
                                 const char* firmware_key_file,
                                 const char* kernel_key_file);
 
diff --git a/utils/firmware_image.c b/utils/firmware_image.c
index a598f54..2e3f924 100644
--- a/utils/firmware_image.c
+++ b/utils/firmware_image.c
@@ -66,6 +66,7 @@
 
   st.remaining_len = image_len;
   st.remaining_buf = firmware_buf;
+  st.overrun = 0;
 
   /* Read and compare magic bytes. */
   StatefulMemcpy(&st, &image->magic, FIRMWARE_MAGIC_SIZE);
@@ -132,7 +133,7 @@
   image->firmware_data = (uint8_t*) Malloc(image->firmware_len);
   StatefulMemcpy(&st, image->firmware_data, image->firmware_len);
 
-  if(st.remaining_len != 0) {  /* Overrun or underrun. */
+  if(st.overrun || st.remaining_len != 0) {  /* Overrun or underrun. */
     Free(firmware_buf);
     return NULL;
   }
@@ -174,6 +175,7 @@
   header_blob = (uint8_t*) Malloc(GetFirmwareHeaderLen(image));
   st.remaining_len = GetFirmwareHeaderLen(image);
   st.remaining_buf = header_blob;
+  st.overrun = 0;
 
   StatefulMemcpy_r(&st, &image->header_len, FIELD_LEN(header_len));
   StatefulMemcpy_r(&st, &image->firmware_sign_algorithm, FIELD_LEN(header_len));
@@ -183,7 +185,7 @@
                  RSAProcessedKeySize(image->firmware_sign_algorithm));
   StatefulMemcpy_r(&st, &image->header_checksum, FIELD_LEN(header_checksum));
 
-  if (st.remaining_len != 0) {  /* Underrun or Overrun. */
+  if (st.overrun || st.remaining_len != 0) {  /* Underrun or Overrun. */
     Free(header_blob);
     return NULL;
   }
@@ -202,12 +204,13 @@
   preamble_blob = (uint8_t*) Malloc(GetFirmwarePreambleLen());
   st.remaining_len = GetFirmwarePreambleLen();
   st.remaining_buf = preamble_blob;
+  st.overrun = 0;
 
   StatefulMemcpy_r(&st, &image->firmware_version, FIELD_LEN(firmware_version));
   StatefulMemcpy_r(&st, &image->firmware_len, FIELD_LEN(firmware_len));
   StatefulMemcpy_r(&st, image->preamble, FIELD_LEN(preamble));
 
-  if (st.remaining_len != 0 ) {  /* Underrun or Overrun. */
+  if (st.overrun || st.remaining_len != 0 ) {  /* Underrun or Overrun. */
     Free(preamble_blob);
     return NULL;
   }
@@ -235,6 +238,7 @@
   firmware_blob = (uint8_t*) Malloc(*blob_len);
   st.remaining_len = *blob_len;
   st.remaining_buf = firmware_blob;
+  st.overrun = 0;
 
   header_blob = GetFirmwareHeaderBlob(image);
   preamble_blob = GetFirmwarePreambleBlob(image);
@@ -251,7 +255,7 @@
   Free(preamble_blob);
   Free(header_blob);
 
-  if (st.remaining_len != 0) { /* Underrun or Overrun. */
+  if (st.overrun || st.remaining_len != 0) { /* Underrun or Overrun. */
     Free(firmware_blob);
     return NULL;
   }
@@ -381,8 +385,8 @@
 int VerifyFirmwarePreamble(RSAPublicKey* firmware_sign_key,
                            const uint8_t* preamble_blob,
                            int algorithm,
-                           int* firmware_len) {
-  uint32_t len;
+                           uint64_t* firmware_len) {
+  uint64_t len;
   int preamble_len;
   uint16_t firmware_version;
 
@@ -400,14 +404,14 @@
 
   Memcpy(&len, preamble_blob + FIELD_LEN(firmware_version),
          sizeof(len));
-  *firmware_len = (int) len;
+  *firmware_len = len;
   return 0;
 }
 
 int VerifyFirmwareData(RSAPublicKey* firmware_sign_key,
                        const uint8_t* preamble_start,
                        const uint8_t* firmware_data_start,
-                       int firmware_len,
+                       uint64_t firmware_len,
                        int algorithm) {
   int signature_len = siglen_map[algorithm];
   uint8_t* digest;
@@ -437,7 +441,8 @@
   int error_code = 0;
   int algorithm;  /* Signing key algorithm. */
   RSAPublicKey* firmware_sign_key = NULL;
-  int firmware_sign_key_len, signature_len, header_len, firmware_len;
+  int firmware_sign_key_len, signature_len, header_len;
+  uint64_t firmware_len;
   const uint8_t* header_ptr = NULL;  /* Pointer to header. */
   const uint8_t* firmware_sign_key_ptr = NULL;  /* Pointer to signing key. */
   const uint8_t* preamble_ptr = NULL;  /* Pointer to preamble block. */
@@ -473,6 +478,7 @@
                                            algorithm,
                                            &firmware_len))) {
     RSAPublicKeyFree(firmware_sign_key);
+    fprintf(stderr, "Couldn't verify Firmware preamble.\n");
     return error_code;  /* AKA jump to recovery. */
   }
   /* Only continue if firmware data verification succeeds. */
@@ -485,6 +491,7 @@
                                        firmware_len,
                                        algorithm))) {
     RSAPublicKeyFree(firmware_sign_key);
+    fprintf(stderr, "Couldn't verify Firmware data.\n");
     return error_code;  /* AKA jump to recovery. */
   }
 
@@ -539,7 +546,7 @@
   /* Get sign key to verify the rest of the firmware. */
   firmware_sign_key_size = RSAProcessedKeySize(image->firmware_sign_algorithm);
   firmware_sign_key = RSAPublicKeyFromBuf(image->firmware_sign_key,
-                                 firmware_sign_key_size);
+                                          firmware_sign_key_size);
   signature_size = siglen_map[image->firmware_sign_algorithm];
 
   if (image->firmware_sign_algorithm >= kNumAlgorithms)
@@ -555,8 +562,8 @@
                FIELD_LEN(preamble));
   preamble_digest = DigestFinal(&ctx);
   if (!RSAVerify(firmware_sign_key, image->preamble_signature,
-                  signature_size, image->firmware_sign_algorithm,
-                  preamble_digest)) {
+                 signature_size, image->firmware_sign_algorithm,
+                 preamble_digest)) {
     error_code = VERIFY_FIRMWARE_PREAMBLE_SIGNATURE_FAILED;
     goto verify_failure;
   }
diff --git a/utils/kernel_image.c b/utils/kernel_image.c
index f92a9f8..32e12a8 100644
--- a/utils/kernel_image.c
+++ b/utils/kernel_image.c
@@ -69,6 +69,7 @@
 
   st.remaining_len = image_len;
   st.remaining_buf = kernel_buf;
+  st.overrun = 0;
 
   /* Read and compare magic bytes. */
   StatefulMemcpy(&st, &image->magic, KERNEL_MAGIC_SIZE);
@@ -154,7 +155,7 @@
   image->kernel_data = (uint8_t*) Malloc(image->options.kernel_len);
   StatefulMemcpy(&st, image->kernel_data, image->options.kernel_len);
 
-  if(st.remaining_len != 0) {  /* Overrun or underrun. */
+  if(st.overrun || st.remaining_len != 0) {  /* Overrun or underrun. */
     Free(kernel_buf);
     return NULL;
   }
@@ -200,6 +201,7 @@
   header_blob = (uint8_t*) Malloc(GetKernelHeaderLen(image));
   st.remaining_len = GetKernelHeaderLen(image);
   st.remaining_buf = header_blob;
+  st.overrun = 0;
 
   StatefulMemcpy_r(&st, &image->header_version, FIELD_LEN(header_version));
   StatefulMemcpy_r(&st, &image->header_len, FIELD_LEN(header_len));
@@ -213,7 +215,7 @@
                    RSAProcessedKeySize(image->kernel_sign_algorithm));
   StatefulMemcpy_r(&st, &image->header_checksum, FIELD_LEN(header_checksum));
 
-  if (st.remaining_len != 0) {  /* Underrun or Overrun. */
+  if (st.overrun || st.remaining_len != 0) {  /* Underrun or Overrun. */
     Free(header_blob);
     return NULL;
   }
@@ -234,6 +236,7 @@
   config_blob = (uint8_t*) Malloc(GetKernelConfigLen());
   st.remaining_len = GetKernelConfigLen();
   st.remaining_buf = config_blob;
+  st.overrun = 0;
 
   StatefulMemcpy_r(&st, &image->kernel_version, FIELD_LEN(kernel_version));
   StatefulMemcpy_r(&st, image->options.version, FIELD_LEN(options.version));
@@ -244,7 +247,7 @@
         FIELD_LEN(options.kernel_load_addr));
   StatefulMemcpy_r(&st, &image->options.kernel_entry_addr,
         FIELD_LEN(options.kernel_entry_addr));
-  if (st.remaining_len != 0) {  /* Overrun or Underrun. */
+  if (st.overrun || st.remaining_len != 0) {  /* Overrun or Underrun. */
     Free(config_blob);
     return NULL;
   }
@@ -272,6 +275,7 @@
   kernel_blob = (uint8_t*) Malloc(*blob_len);
   st.remaining_len = *blob_len;
   st.remaining_buf = kernel_blob;
+  st.overrun = 0;
 
   header_blob = GetKernelHeaderBlob(image);
   config_blob = GetKernelConfigBlob(image);
@@ -287,7 +291,7 @@
   Free(config_blob);
   Free(header_blob);
 
-  if (st.remaining_len != 0) {  /* Underrun or Overrun. */
+  if (st.overrun || st.remaining_len != 0) {  /* Underrun or Overrun. */
     Free(kernel_blob);
     return NULL;
   }
@@ -451,9 +455,10 @@
 int VerifyKernelConfig(RSAPublicKey* kernel_sign_key,
                        const uint8_t* config_blob,
                        int algorithm,
-                       int* kernel_len) {
-  uint32_t len, config_len;
-  config_len = GetKernelConfigLen();
+                       uint64_t* kernel_len) {
+  uint64_t len;
+  int config_len;
+  config_len = GetKernelConfigLen(NULL);
   if (!RSAVerifyBinary_f(NULL, kernel_sign_key,  /* Key to use */
                          config_blob,  /* Data to verify */
                          config_len,  /* Length of data */
@@ -465,14 +470,14 @@
          config_blob + (FIELD_LEN(kernel_version) + FIELD_LEN(options.version) +
                               FIELD_LEN(options.cmd_line)),
          sizeof(len));
-  *kernel_len = (int) len;
+  *kernel_len = len;
   return 0;
 }
 
 int VerifyKernelData(RSAPublicKey* kernel_sign_key,
                      const uint8_t* kernel_config_start,
                      const uint8_t* kernel_data_start,
-                     int kernel_len,
+                     uint64_t kernel_len,
                      int algorithm) {
   int signature_len = siglen_map[algorithm];
   uint8_t* digest;
@@ -505,7 +510,8 @@
   int kernel_sign_algorithm;  /* Kernel Signing key algorithm. */
   RSAPublicKey* kernel_sign_key;
   int kernel_sign_key_len, kernel_key_signature_len, kernel_signature_len,
-      header_len, kernel_len;
+      header_len;
+  uint64_t kernel_len;
   const uint8_t* header_ptr;  /* Pointer to header. */
   const uint8_t* kernel_sign_key_ptr;  /* Pointer to signing key. */
   const uint8_t* config_ptr;  /* Pointer to kernel config block. */