There are many ways to install an AIX server or VIOS:
Install VIOS from VIOS DVD media using the allocated physical DVD drive.
Install VIOS from the HMC command line using the installios command. The installios command has a progressive wizard that guides you through the installation process.
Install VIOS using the IBM Network Installation Manager (NIM).
Install AIX from a Linux server using NIMOL (package provide into the base AIX CD)
NEW using AIX 7.1TL5 or AIX 7.2TL2 you can use a USB key (min. 16GB)
Copy you ISO (first) from a linux on the USB key using dd command:
$ dd if=/AIX7200-02-01.iso of=/dev/usbms0 bs=4k
Debug mode for install
To enable the debug mode during AIX installation, first start the install… select console… select language… In the Installation menu