After the firmware attempts to upgrade, is there anything in the logs? # show logging. This could be a hardware issue with the switch. One last thing I would try doing is applying the firmware through the XMODEM method. In the firmware download there is an update guide. On page 19 of the update guide it details the steps to booting to the advanced menu and applying the firmware through XMODEM. This will take a while for it to finish. Keep us posted.
Hi All I have a stack of 4 M6220 switches, I have just updated the firmware to 5.1 all went well apart from switch 1 a member switch.  I upload the image and set the switch to use image 2 the reload fails and the image disappears, now the auto update just keeps cycling and the switch 1 has been greyed out in all the settings.  It continues to say updating in the GUI. Any ideas how I can force the update onto that last switch, it is very frustrating and time consuming - can anybody help?  Thanks Eric
M6220 switch stack problem