2 files changed, 34 insertions, 4 deletions

diff --git a/cgpt/cgpt_legacy.c b/cgpt/cgpt_legacy.c
index b7582123..d5df34d5 100644
--- a/cgpt/cgpt_legacy.c
+++ b/cgpt/cgpt_legacy.c
@@ -10,6 +10,7 @@
 
 int CgptLegacy(CgptLegacyParams *params) {
   struct drive drive;
+  int gpt_retval;
   GptHeader *h1, *h2;
 
   if (params == NULL)
@@ -19,14 +20,32 @@ int CgptLegacy(CgptLegacyParams *params) {
                            params->drive_size))
     return CGPT_FAILED;
 
+  if (GPT_SUCCESS != (gpt_retval = GptSanityCheck(&drive.gpt))) {
+    Error("GptSanityCheck() returned %d: %s\n",
+          gpt_retval, GptError(gpt_retval));
+    return CGPT_FAILED;
+  }
+
   h1 = (GptHeader *)drive.gpt.primary_header;
   h2 = (GptHeader *)drive.gpt.secondary_header;
-  if (params->efipart) {
+  if (params->mode == CGPT_LEGACY_MODE_EFIPART) {
+    drive.gpt.ignored = MASK_NONE;
     memcpy(h1->signature, GPT_HEADER_SIGNATURE, GPT_HEADER_SIGNATURE_SIZE);
     memcpy(h2->signature, GPT_HEADER_SIGNATURE, GPT_HEADER_SIGNATURE_SIZE);
     RepairEntries(&drive.gpt, MASK_SECONDARY);
     drive.gpt.modified |= (GPT_MODIFIED_HEADER1 | GPT_MODIFIED_ENTRIES1 |
                            GPT_MODIFIED_HEADER2);
+  } else if (params->mode == CGPT_LEGACY_MODE_IGNORE_PRIMARY) {
+    if (!(drive.gpt.valid_headers & MASK_SECONDARY) ||
+        !(drive.gpt.valid_entries & MASK_SECONDARY) ||
+        drive.gpt.ignored & MASK_SECONDARY) {
+      Error("Refusing to mark primary GPT ignored unless secondary is valid.");
+      return CGPT_FAILED;
+    }
+    memset(h1, 0, sizeof(*h1));
+    memcpy(h1->signature, GPT_HEADER_SIGNATURE_IGNORED,
+           GPT_HEADER_SIGNATURE_SIZE);
+    drive.gpt.modified |= GPT_MODIFIED_HEADER1;
   } else {
     memcpy(h1->signature, GPT_HEADER_SIGNATURE2, GPT_HEADER_SIGNATURE_SIZE);
     memcpy(h2->signature, GPT_HEADER_SIGNATURE2, GPT_HEADER_SIGNATURE_SIZE);
diff --git a/cgpt/cmd_legacy.c b/cgpt/cmd_legacy.c
index 5fd742cc..e45b305c 100644
--- a/cgpt/cmd_legacy.c
+++ b/cgpt/cmd_legacy.c
@@ -19,6 +19,7 @@ static void Usage(void)
          "                 default 0, meaning partitions and GPT structs are\n"
          "                 both on DRIVE\n"
          "  -e           Switch GPT header signature back to \"EFI PART\"\n"
+         "  -p           Switch primary GPT header signature to \"IGNOREME\"\n"
          "\n", progname);
 }
 
@@ -31,7 +32,7 @@ int cmd_legacy(int argc, char *argv[]) {
   int errorcnt = 0;
 
   opterr = 0;                     // quiet, you
-  while ((c=getopt(argc, argv, ":heD:")) != -1)
+  while ((c=getopt(argc, argv, ":hepD:")) != -1)
   {
     switch (c)
     {
@@ -44,9 +45,19 @@ int cmd_legacy(int argc, char *argv[]) {
       }
       break;
     case 'e':
-      params.efipart = 1;
+      if (params.mode) {
+        Error("Incompatible flags, pick either -e or -p\n");
+        errorcnt++;
+      }
+      params.mode = CGPT_LEGACY_MODE_EFIPART;
+      break;
+    case 'p':
+      if (params.mode) {
+        Error("Incompatible flags, pick either -e or -p\n");
+        errorcnt++;
+      }
+      params.mode = CGPT_LEGACY_MODE_IGNORE_PRIMARY;
       break;
-
     case 'h':
       Usage();
       return CGPT_OK;