bitcrab have you tried
update_asset TCNY null { "id": "1.3.734", "symbol": "TCNY", "precision": 4, "issuer": "1.2.121", "options": { "max_supply": "1000000000000000", "market_fee_percent": 0, "max_market_fee": "1000000000000000", "issuer_permissions": 511, "flags": 128, "core_exchange_rate": { "base": { "amount": 103, "asset_id": "1.3.734" }, "quote": { "amount": 46825, "asset_id": "1.3.0" } }, "whitelist_authorities": [], "blacklist_authorities": [], "whitelist_markets": [], "blacklist_markets": [], "description": "smartcoin defined by transwiser", "extensions": [] } true
That should set your permissions and your flags back to where they were.