Side B Atari imaging problem

[SomeGuy]

This appears to be a 1.2mb drive? Most 1.2.mb drives have built in "smarts" where it must detect an index hole before the drive will ever enter the "ready" state and output data. Most 360K drives do not have this feature and will output data regardless.

You might try consulting the manual for this specific model of drive to see if there are any jumpers that might help. But overriding that behavior is not a common option.