Is there any way to downgrade iPod 4g from 6.1 to 4.2.1 without a computer?
There is no way to downgrade iPod 4G from 6.1 to 4.2.1 without a computer. This is because you will need to connect your iPod to the computer for the downgrade process to begin with the Redsn0w platform.
No you will need a computer do downgrade. Sorry