Hello there:

I know that exist a procedure to convert an OS using 32bits kernel to 64 bits kernel. But, exist a procedure to convert an OS using 64bits to 32 bits kernel?
Please help me.

Regards.

There is a link in the root directory called /unix. It points to the kernel you are using (in case of a 64-bit-kernel this is /usr/lib/boot/unix_64). Remove the link and create a new one to the kernel of your liking, then reboot.

You may have to install the 32-bit-kernel images first, check with "lslpp -l bos.mp*" and "lslpp -l bos.up*" (mp=multiprocessor, up=uniprocessor kernels) which kernels are installed.

bakunin

If you want to enable 64-bit kernel after system installation, you will need to
instruct the system to use the 64-bit kernel information stored in the /usr/lib/boot
directory. There are two kernels available in the /usr/lib/boot directory:
unix_mp 32-bit kernel for multiprocessor systems
unix_64 64-bit kernel for 64-bit processor systems

The following example provides the commands to run to enable the 64-bit kernel
after system installation:

# ln -sf /usr/lib/boot/unix_64 /unix
# ln -sf /usr/lib/boot/unix64 /usr/lib/boot/unix
# bosboot -ad /dev/ipldevice
bosboot: Boot image is 23137 512 byte blocks.
# shutdown -r

After the system has rebooted, it will be running the 64-bit kernel. To reactivate
the 32-bit kernel, follow the same procedure, substituting unix_mp for unix_64,
depending on your system type.

To verify your settings, execute the following command:
# ls -al /unix
lrwxrwxrwx 1 root system 21 Nov 11 11:30 /unix -> /usr/lib/boot/unix_64