LTM SW downgrade from 11.1.0 to 9.3.1?

You can't run 9.3.x on the 64 bit platforms (1600 and newer) and you can't run 11.1.0 on the 32 bit platforms (1500, 3400) so unless you have a 6400, 6800, or 8400 this is a non-starter.

If you have the right platform, this will probably work. You need a USB CD-ROM that the BIG-IP will boot from, iso images for 10.0.0 and 9.3.1, a serial cable, a console emulator and a scp client. A thumb drive isn't going to work.

1. Backup the important parts of the config. Even if you haven't actually done any configuration yet, you will still need to get the base registration key off the box so that you can license the box once you are done. This file is /config/RegKey.license. Get it off the box using scp:

`scp root@192.168.1.245:/config/RegKey.license ./`

2. Using a USB CD-ROM boot from a 10.0.0 release iso. This is the simplest way around a problem that 10.1.0 boot loaders have with RAID arrays and you need a 10.x to get the option of partitions or volumes in diskinit. Once the system is up, connect to the serial console, log-in, and use the diskinit command to remove the LVM and RAID array (since the older version of diskinit doesn’t support RAID, you can’t use the –noarray option, and it won’t build an array even on platforms that support it):

`diskinit --style partitions`

When this step is done, you will have a very expensive paperweight, as the hard drives of the BIG-IP will be blank.

3. Using a USB CDROM, boot from the 9.3.x iso, select the "Install" option from the on-screen menu, and install 9.3.x in HD1.1. The install will run and when it is finished it will tell you to disconnect the USB device and hit enter to reboot the box.

4. If required, install Hotfix roll-ups. Use scp to put them in /shared and im to install:

From a host with the software: `scp Hotfix-BIGIP-version-HFx.im root@192.168.1.245:/shared`

On the BIG-IP: ` im Hotfix-BIGIP-version-HFx.im `

This will install and prompt you to reboot. Use `full_box_reboot` to reboot.

5. License the box as normal, using the registration key you took off the box in step 1.

6. The downgrade is complete – you now have a brand new box that has only v9 code on it.

To go back, upgrade to 9.4.1, then to 9.4.8, then to 10.0.0, then to 11.1.0. Or wipe the drives again with the 10.0.0 disk and install 11.1.0 from the iso.