While ESS provides the base "bootable" ISOs, incremental updates and patches are found elsewhere.
Select or IBM Operating Systems -> AIX -> Version 6.1 . aix 61 cd iso download upd
Getting the right installation media for IBM AIX 6.1 is a common task for administrators maintaining legacy Power Systems environments. To download AIX 6.1 CD or DVD ISO images, you must use official IBM portals, as IBM does not authorize direct delivery of these images through support channels. Where to Download AIX 6.1 ISO Images While ESS provides the base "bootable" ISOs, incremental
Run smitty update_all from the directory containing the new filesets to apply the updates. Key Technical Details for AIX 6.1 Downloading an AIX ISO for a specific OSLEVEL - IBM To download AIX 6
Choose or Service Packs and download the required filesets (often over 2GB). Transfer the files to your AIX system in binary mode .