Edit the "chain" table in the DB directly
Code:
update chain set chain_address_version=unhex('6F') where chain_name='Darkcoin';
and rescan the blockchain again.
mysql> select * from chain;
+----------+----------+-----------+------------+-------------+-----------------------+---------------------+
| chain_id | magic_id | policy_id | chain_name | chain_code3 | chain_address_version | chain_last_block_id |
+----------+----------+-----------+------------+-------------+-----------------------+---------------------+
| 1 | 1 | 1 | Darkcoin | DRK | L | 71216 |
+----------+----------+-----------+------------+-------------+-----------------------+---------------------+
1 row in set (0.01 sec)
mysql> update chain set chain_address_version=unhex('6F') where chain_name='Darkcoin';
Query OK, 1 row affected (0.02 sec)
Rows matched: 1 Changed: 1 Warnings: 0
mysql> select * from chain;
+----------+----------+-----------+------------+-------------+-----------------------+---------------------+
| chain_id | magic_id | policy_id | chain_name | chain_code3 | chain_address_version | chain_last_block_id |
+----------+----------+-----------+------------+-------------+-----------------------+---------------------+
| 1 | 1 | 1 | Darkcoin | DRK | o | 71216 |
+----------+----------+-----------+------------+-------------+-----------------------+---------------------+
1 row in set (0.00 sec)
BAM!!! God you are good.
Edit: Didn't seem like a rescan was needed.