from my notes (for x350 with old firmware):
1) download correct ssh.xmod version for Your switch
* switch4.5 # show switch
Primary ver: 12.6.2.10
Config Selected: primary.cfg
Config Booted: primary.cfg
2) start tftp on you LAN pc (for me it working on IP:192.168.1.159)
* switch4.6 # download image 192.168.1.159 summitX-12.6.2.10-patch1-15-ssh.xmod vr "VR-Default" primary
Do you want to install image after downloading? (y - yes, n - no, - cancel) Yes
Downloading to Switch.......
This image will be used only after rebooting the switch!
Installing to primary partition!
Installing to Switch............................................................
SSL will be usable after restart of thttpd process. Restart snmpMaster process to use AES/3DES users for SNMPv3.
Image installed successfully
* switch4.7 # run update
* switch4.8 # reboot
Do you want to save configuration changes to currently selected configuration
file (primary.cfg) and reboot?
(y - save and reboot, n - reboot without save, - cancel command) Yes
Saving configuration on master ............................ done!
That it. Do you want to save configuration changes to currently selected configuration
file (primary.cfg) and reboot?
(y - save and reboot, n - reboot without save, - cancel command) Yes
Saving configuration on master ............................ done!
It help me, hope You too.