MuscleNerd has confirmed to iClarified that most devices can be downgraded from iOS 5 beta 1 to iOS 4.x so long as you have your SHSH Blobs saved.
The only exception is the iPad 2 which cannot be downgraded at all until a bootrom-level or iboot-level exploit is developed.
This information may be helpful to developers who are thinking about upgrading their device but may need to revert back to iOS 4.x in the future.
For anyone else who is thinking of upgrading to the iOS 5 beta, make sure you remember that your baseband will be updated, affecting your ability to unlock. Downgrading your firmware will not downgrade your baseband. So update with caution.
The only exception is the iPad 2 which cannot be downgraded at all until a bootrom-level or iboot-level exploit is developed.
This information may be helpful to developers who are thinking about upgrading their device but may need to revert back to iOS 4.x in the future.
For anyone else who is thinking of upgrading to the iOS 5 beta, make sure you remember that your baseband will be updated, affecting your ability to unlock. Downgrading your firmware will not downgrade your baseband. So update with caution.