Index: sbin/geom/class/part/gpart.8
===================================================================
--- sbin/geom/class/part/gpart.8
+++ sbin/geom/class/part/gpart.8
@@ -933,6 +933,11 @@
 See
 .Xr gptboot 8
 for more details.
+.It Cm lenovofix
+Setting this attribute writes a new GPT pMBR with the 0xee partition in the 2nd
+slot instead of the first. This resolves a BIOS compatibility issue in some
+Lenovo models including the X220, T420, and T520, allowing them to boot from
+GPT partitioned disks without EFI.
 .El
 .Pp
 The scheme-specific attributes for MBR:
Index: sys/geom/part/g_part_gpt.c
===================================================================
--- sys/geom/part/g_part_gpt.c
+++ sys/geom/part/g_part_gpt.c
@@ -1007,6 +1007,7 @@
 {
 	struct g_part_gpt_entry *entry;
 	struct g_part_gpt_table *table;
+	struct g_provider *pp;
 	uint8_t *p;
 	uint64_t attr;
 	int i;
@@ -1036,6 +1037,22 @@
 			}
 		}
 		return (0);
+	} else if (strcasecmp(attrib, "lenovofix") == 0) {
+		/*
+		 * Write the 0xee GPT entry to slot #1 (2nd slot) in the pMBR.
+		 * This workaround allows Lenovo X220, T420, T520, etc to boot
+		 * from GPT Partitions in BIOS mode.
+		 */
+
+		if (entry != NULL)
+			return (ENXIO);
+
+		pp = LIST_FIRST(&basetable->gpt_gp->consumer)->provider;
+		bzero(table->mbr + DOSPARTOFF, DOSPARTSIZE * NDOSPART);
+		gpt_write_mbr_entry(table->mbr, 1, 0xee, 1,
+		    MIN(pp->mediasize / pp->sectorsize - 1, UINT32_MAX));
+		le16enc(table->mbr + DOSMAGICOFFSET, DOSMAGIC);
+		return (0);
 	}
 
 	if (entry == NULL)