Increase the /usr PP (Physical Partition) number with the command:
chlv -x 512 hd2

Mount /tmp with the command :
mount /dev/hd3 /tmp

Note: If the tmp logical volume name is different from /dev/hd3 the migration will fail. It is recommended that your /tmp file system has at least 40 MB of free space; if necessary, free in /tmp or extend the file system with SMIT or the chfs command (example here to increase /tmp with 20,000 512 blocks = 10 MB) :
chfs -a size='+20000' /tmp
Be aware that if the disk is completely full, you may not be able to increase the size of the /tmp or /etc if they are too small. If this is the case, make a backup (smit mksysb), and restore with the shrink option. The minimum free disk space required is 200 MB. Check the rootvg place and PP size with the command:
lsvg rootvg

If you have a system disk less than 4GB or if the PP size is 4MB, it is better to extend the hd5 partition. If you do not extend hd5, you may have the following problem:
0301-161 bosboot: dd failed to copy boot image
0301-165 bosboot: WARNING! System not bootable

To extend the hd5 partition:
check the PP number of hd5 with the command:
lspv -p hdiskXX| grep -i boot (hdiskXX is rootvg)
Only 1 PP : 1-1 used outer edge hd5 boot N/A

if the PP number is 1 extend it with the command:
extendlv hd5 1
Note : the two hd5 PP have to be contiguous.
Two PP not contiguous :1-1 used outer edge hd5 boot N/A
13-13 used outer edge hd5 boot N/A
If it is not, you have to remove hd5 and create it again with the commands:
rmlv -f hd5
mklv -y hd5 -t boot -u2 rootvg 2 hdiskXX
lspv -p hdiskXX | grep -i boot (for checking)

( Two PP contiguous : 162-163 used outer middle hd5 boot N/A)
bosboot -a -d /dev/ipldevice