The 650 I think requires you to be in a specific port. This is what I have from my notes a long while back (RUN AT YOUR OWN RISK):
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The 6xx models use a JFFS2 F/S on raw NAND Flash. To delete and recreate the /flash partition from cpboot you need to run the command actually a u-boot alias in the environment) "run wipe-out-flash". If cpboot can't find the command alias for "wipe-out-flash" you need to execute "purgeenv" first. This function is implemented in the default environment. The image partitions get deleted and recreated whenever "upgrade" is used to upgrade an image partition.
1. Console into the controller's serial port and reload the controller and interrupt the boot to 'cpboot>'
2. From 'cpboot', enter 'purgeenv'
3. From 'cpboot', enter 'run wipe-out-flash', this will wipe the flash
4. Connect your laptop ethernet interface to Gig1/1
5. Start up the TFTP server and put the firmware you wish to load into the TFTP directory
6. Run the following commands to set the IP address and TFTP server IP
a. setenv ipaddr <ipaddress>
b. setenv netmask <netmask>
c. setenv gatewayip <gateway>
d. setenv serverip <tftp-serverip>
7. Enter the command 'upgrade 0 <firmware-name>'.
8. Once done, enter 'boot' at 'cpboot>' to reload the controller wiht the new firmware.
Once this is done, the controller will be back in factory-default mode and can be re-configured, restored, etc.
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