Cannot install V4R3 on 720??

The minimum OS for model 720 is V4R3.
When we tried to install in, it failed on 2 systems with different size of load source disks (#6607 4GB, #6717 8.5GB, #6817 17GB).

After the study, realize that the system installed RAID controller card #2748 required minimum OS V4R4.

Problem resolved after change the RAID card to #2741 or #2740.