cmd: gpt: Preserve bootable flag

Sets the bootable flag when constructing the partition string from the
current partition configuration. This ensures that when the partitions
are written back (for example, when renaming a partition), the flag is
preserved.

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
diff --git a/cmd/gpt.c b/cmd/gpt.c
index 9cc7293..d525603 100644
--- a/cmd/gpt.c
+++ b/cmd/gpt.c
@@ -176,6 +176,7 @@
 #ifdef CONFIG_PARTITION_TYPE_GUID
 	partlistlen += numparts * (strlen("type=,") + UUID_STR_LEN + 1);
 #endif
+	partlistlen += numparts * strlen("bootable,");
 	partlistlen += numparts * (strlen("uuid=;") + UUID_STR_LEN + 1);
 	/* for the terminating null */
 	partlistlen++;
@@ -316,6 +317,8 @@
 		strcat(partitions_list, ",uuid=");
 		strncat(partitions_list, curr->gpt_part_info.uuid,
 			UUID_STR_LEN + 1);
+		if (curr->gpt_part_info.bootable & PART_BOOTABLE)
+			strcat(partitions_list, ",bootable");
 		strcat(partitions_list, ";");
 	}
 	return 0;
diff --git a/test/py/tests/test_gpt.py b/test/py/tests/test_gpt.py
index 93007de..b4c03bc 100644
--- a/test/py/tests/test_gpt.py
+++ b/test/py/tests/test_gpt.py
@@ -143,6 +143,7 @@
             "size": "0x100000",
             "type": "0fc63daf-8483-4772-8e79-3d69d8477de4",
             "uuid": "33194895-67f6-4561-8457-6fdeed4f50a3",
+            "bootable": True,
         },
         {
             "name": "part2",