MySQL Version upgrade

Hello all,
Recently i have changed the MySQL version from 5.2 to 5.6.26, but i am facing some I/O issues. In 5.6 the disk I/O has increase tremendously.
70% of my tables are of MyISAM and rest InnoDB. I have 2 GB of RAM, and Compact Flash of 30GB to Work with. Can anyone help me in reducing the IO and tell me the right configuration.

Can you post pt-summary / pt-mysql-summary outputs to review your existing configuration ? As this would help to advise proper configuration tuning.