Modifying the kernel_utility tool to create our magic blob.

src/platform/vboot_reference/vboot_firmware/stub/utility_stub.c

Index: src/platform/vboot_reference/vboot_firmware/stub/utility_stub.c
diff --git a/src/platform/vboot_reference/vboot_firmware/stub/utility_stub.c b/src/platform/vboot_reference/vboot_firmware/stub/utility_stub.c
index 66132703ea63e57d13d2d9c364a89ed1e5679081..7a028e7bec68dc9b9b67dd45371749a4746768b5 100644
--- a/src/platform/vboot_reference/vboot_firmware/stub/utility_stub.c
+++ b/src/platform/vboot_reference/vboot_firmware/stub/utility_stub.c
@@ -96,3 +96,17 @@ const void* StatefulMemcpy_r(MemcpyState* state, const void* src,
   state->remaining_len -= len;
   return src;
 }
+
+const void* StatefulMemset_r(MemcpyState* state, const uint8_t val,
+                             uint64_t len) {
+  if (state->overrun)
+    return NULL;
+  if (len > state->remaining_len) {
+    state->overrun = 1;
+    return NULL;
+  }
+  Memset(state->remaining_buf, val, len);
+  state->remaining_buf += len;
+  state->remaining_len -= len;
+  return state;                         // have to return something non-NULL
+}