--- gpt.c.sav	2018-11-18 09:12:44.192447000 +0100
+++ gpt.c	2019-01-25 19:43:16.186589000 +0100
@@ -312,6 +312,47 @@
 	return (0);
 }
 
+static uint64_t
+gpt_recover(struct dsk *dskp, struct gpt_hdr *hdr_prim,
+                const struct gpt_hdr *hdr_back)
+{
+	printf("%s: trying to recover GPT...\n", BOOTPROG);
+	const int head_prim_lba = 1;
+	const int table_prim_lba = 2;
+                
+	/* Copy partition table backup -> primary */
+	int n_sect = DEV_BSIZE / hdr_back->hdr_entsz;
+	n_sect = hdr_back->hdr_entries / n_sect;
+
+	/* Copy sector by sector because no assumption is
+	* made about n_sect value and secbuf size */
+	for (int i = 0; i < n_sect; i++) {
+		if (drvread(dskp, secbuf, hdr_back->hdr_lba_table + i, 1))
+			goto recover_failed;
+		if (drvwrite(dskp, secbuf, table_prim_lba + i, 1))
+			goto recover_failed;
+	}
+                
+	/* Set GPT primary header with backup header */
+	*hdr_prim = *hdr_back;
+	hdr_prim->hdr_crc_self = 0;
+	hdr_prim->hdr_lba_self = head_prim_lba;
+	hdr_prim->hdr_lba_alt = hdr_back->hdr_lba_self;
+	hdr_prim->hdr_lba_table = table_prim_lba;
+	hdr_prim->hdr_crc_self = crc32(hdr_prim, hdr_prim->hdr_size);
+	bzero(secbuf, DEV_BSIZE);
+	bcopy(hdr_prim, secbuf, hdr_prim->hdr_size);
+	if (drvwrite(dskp, secbuf, hdr_prim->hdr_lba_self, 1))
+		goto recover_failed;
+            
+	printf("%s: GPT recovering -> SUCCESS\n", BOOTPROG);
+	return (hdr_prim->hdr_lba_self);
+                
+recover_failed:
+	printf("%s: GPT recovering -> FAILED\n", BOOTPROG);
+	return (0);
+}
+
 int
 gptread(const uuid_t *uuid, struct dsk *dskp, char *buf)
 {
@@ -352,10 +393,23 @@
 	    gptread_table("backup", uuid, dskp, &hdr_backup,
 	    table_backup) == 0) {
 		hdr_backup_lba = hdr_backup.hdr_lba_self;
+
+		/* If primary GPT is dammaged but backup GPT is ok 
+		 * we try to recover primary GPT */
 		if (hdr_primary_lba == 0) {
 			gpthdr = &hdr_backup;
 			gpttable = table_backup;
-			printf("%s: using backup GPT\n", BOOTPROG);
+			hdr_primary_lba = gpt_recover(dskp, &hdr_primary,
+				&hdr_backup);
+			if (hdr_primary_lba == 0) {
+				printf("%s: using backup GPT\n", BOOTPROG);
+			} else {
+				if (!gptread_table("primary", uuid, dskp,
+					&hdr_primary, table_primary)) {	
+					gpthdr = &hdr_primary;
+					gpttable = table_primary;
+				}
+			}
 		}
 	}