I have 13 Aruba 3500 switches all the same model and I am trying to upgrade the OS on them. I was able to successfully upgrade 3 of them and then it would not work and it just hangs at "Upgrading the Image" this happens right after the FTP transfer is completed. All the switches are brand new and out of the box. I get a base config on them so I can access via web browser and then I try the OS upgrade from the GUI. Then on the ones that hang I try to do the upgrade again and it says it will not over write the file. The OS I am upgrading to is ArubaOS_MAS_7.1.3.0_33279
What can I do to get this to work?