3Com VCX V7000 Maintenance Manual page 313

The order of the A and B versions may be reversed depending on the
upgrade history of the system.
c When you are downgrading, use the earlier of the two operating
system versions in this command:
vcx-os-switch 4.2.0
d To confirm that you have selected the operating system version that
you want, repeat the
"selected" appears in the Status column for the version that you
want.
Example:
OS Version
A 4.2.0
B 4.2.1
4 Reboot the system using this command:
reboot
When the system reboots, it starts VCX 7.1.x services.
Downgrading a Branch Office Server
If you attempt to upgrade a branch office server but the upgrade is
unsuccessful, you must downgrade and contact 3Com Support for
assistance.
Switch VCX Version
To switch the VCX version:
1 Log in as root and enter this command:
vcx-switchversion --manual 7.x
Example:
vcx-switchversion --manual 7.1.0c
The
vcx-switchversion
Stops VCX services
■
Changes a link to point to the requested VCX version
■
Issues a warning that databases must be restored
■
CAUTION: Do not reboot the system or restart VCX services until
databases have been restored. The VCX 7.1.x version has been selected
Downgrading from 7.1.y to 7.1.x
vcx-os-query
Partition
/dev/hda2
/dev/hda3
command:
command. Verify that the word
Label
/A
/B
313
Status
selected
active