Stuck on installing firmware update

I have tried to update to the latest firmware for PR4100 but for some time now it has been stuck on “installing firmware update” everything on the dashboard does load ok CPU is at 99%, can i power cycle the NAS (will that help) or should i keep on waiting?

How long does it usually take?

Thanks.

Same here. Just hangs.

In the end i powered it down and on again.
Everything seems to be back to normal, CPU is normal now but ill leave the update.