Booting SLES from a .ISO

WE have a SLES server 12 SP4, we want to upgrade it to SLES 12 SP5. Since the server is not in the internet we cannot do a online installation. In addition the server do not have any flash drives either so booting from a .ISO is only option. However we are not seeing any clear documentation on how to do that? Can someone kindly share the steps?

@sujeeth_kamath Hi so you have a DVD device in the system? See

You just need DVD 1 and writeable DVD media to put the image onto with eg Brasero, when burning the image, make sure you use the slowest speed possible as well.

Thanks a lot Malcom for response. unfortunately the server do not have a DVD drive. We only have the option of booting from the .iso so here is what we are looking for
a. Copy the .iso to the server
b. Change the settings so that .iso also show up a booting mechanism - Not sure what are the settings
c. Reboot and go ahead with the update.
Any help in this regard is highly appreciated

@sujeeth_kamath See this thread about adding the iso image to grub;