unmanagement mode on 2824

Hi all,

i'am trying to switch from unmanagement to management mode on a 2824 but It dosen't work.

I pressed the button mode on the front panel for more than 7 seconds, then the switch has rebooted. During the reboot I had the green light mode Flashing.

And when the switch has finished to reboot, It was in an unmanagement mode again :/

Do you have any idea why It starts alway with the unmanagement mode ?

thank you for your help.