update USB kali linux w/ persistance & keep old persistance information

I have an 8GB USB stick with Kali live Linux 32-bit installed with a persistence partition.

Kali w/ persistence was installed using the standard instructions located here:
http://docs.kali.org/downloading/kal...sb-persistence

The current kali image installed is v 1.0.9a

I would like to update the kali image to v 1.1.0a

Is there a way to update the kali image & keep the existing persistence partition information intact/undamaged?

can you please detail the process?

thanks..