Blackhole engine and utf8 character set

[Craig Healey]

I'm replicating a 5.5 DB to 5.6. The default storage engine on 5.5 is InnoDB, and on 5.6 is Blackhole. The character set system variables are all the same. Creating the tables, all work except one.

create table t1 (
`uuid` varchar(255) NOT NULL,
`device_uuid` varchar(255) NOT NULL,
`created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
`updated_at` timestamp NULL DEFAULT NULL,
PRIMARY KEY (`uuid`,`device_uuid`,`created_at`)
) DEFAULT CHARSET=utf8;

ERROR 1071 (42000): Specified key was too long; max key length is 1000 bytes

I can create the table as InnoDB, and I know utf8 in MySQL isn't "actually" utf8. But I wondered if anyone knew the reason why InnoDB and Blackhole don't produce the same error?