The Symbol Device Driver supports OS upgrade and downgrade using telnet and SSH login protocols and FTP/TFTP file transfer mechanisms.

The Symbol firmware releases 1.5.0, 1.5.1, 2.0.0, and 2.1.0 have all been qualified and tested with the upgrade/downgrade process. One issue was found when completing an upgrade or downgrade between the 2.0.0 and 2.1.0 releases using the SSH protocol.

The Symbol device 2.0.0 and 2.1.0 firmware returns different fingerprints for the RSA key. Therefore, after the upgrade/downgrade, attempts to login using SSH will fail, due to the key exchange.

From the application, the per/downgrade will show Failed, based on failure to login following the device reboot, due to SSH host key verification. Suggestions for managing this issue are as follows.

  • If possible at your site, using telnet for the OS upgrade/downgrade between 2.0.0 and 2.1.0 allows the process to proceed normally and return status of the state of the device.

  • If using SSH for OS upgrade, check the error status looking for a successful upload, followed by an SSH failure to connect. This is the failure signature indicating the RSA key mismatch between firmware releases.

  • In either case, you need to update the SSH host key database on the HP device server to regain access to the device.

    • For Linux and Solaris Servers: The SSH key database is located in the ~root/.ssh/sshhostkeys file. Edit the sshhostkeys file, and remove the entry associated with the Symbol device based on IP address.

    • For Windows Servers: The host key database is maintained in the Registry, in the HKEY_LOCAL_MACHINE\SOFTWARE\Voyence\Control\SshHostKeys folder. Using the regedit utility, remove the entry associated with the Symbol device based on IP address.