Updating from SLES 11 PL3 to PL4
I am currently running SLES 11 PL3 and have downloaded the ISO for SLES 11 PL 4. This is burned to a DVD and I have booted from it.
Note: I am using a version of SLES 11 PL4 for SAP Business One (B1) but as far as I know the installation/upgrade is not different.
I only want to upgrade - not destructively re-install.
The form gives me three options:
1. Boot from Hard Disk
2. Install SLES 11 SP4 B1
3. Failsafe -- Install SLES 11 SP4 B1.
Whether I pick option 2 or 3 it warns me that all the data on the main system disk will be destroyed.
Is there a way to non-destructively upgrade to PL 4 using media as I am doing? Or do I have to use Zypper as is described elsewhere?
I have found some information that there is an "update only" option on the media but I have not found a way to invoke it.
Thanks for any help.