This is the procedure I’ve used to upgrade the firmware of my PowerConnect 5448 and 5424 switches. You should have set up a tftp server in same network as switch admin ip is. There are plenty of howtos to do this in the web like this, so I assume that you have already running the tftp server.
First, connect to to your switch via ssh or serial cable and enable privileged commands:
> enable
Copy new firmware from your tftp server:
# copy tftp://tftp_server_ip/switch/powerconnect_54xx-20046.ros image
# copy tftp://tftp_server_ip/switch/powerconnect_54xx_boot-2000.rfb boot
Now, you should view the new firmware image ready, but not active:
# show bootvar
Image Filename Version Date Status
----- --------- --------- --------------------- -----------
1 image-1 1.0.0.31 31-Oct-2007 10:32:13 Active*
2 image-2 2.0.0.46 14-Apr-2011 13:10:53 Not active
"*" designates that the image was selected for the next boot
Select image-2 as active for the next boot:
# boot system image-2
The image is selected as active for the next system boot
# show bootvar
Image Filename Version Date Status
----- --------- --------- --------------------- -----------
1 image-1 1.0.0.31 31-Oct-2007 10:32:13 Active
2 image-2 2.0.0.46 14-Apr-2011 13:10:53 Not active*
Now, we only have to reload the switch to boot with updgraded image.
# reload
I’ve upgraded several switches and in all of them the switch configuration has been preserved.