Crashed during update and won't connect

My UE Boom 2 crashed during the process of updating firmware via UEBOOM app in iPod touch.

Now it won't update and won't connect. When I try to update via USB on my Mac, the updater app says it is already updated to the latest version.

When the Boom is turned on, the bluetooth light blinks rapidly. It won't connect to any devices over bluetooth any more.

Factory reset makes no difference.

So basically, my UE BOOM2 is now broken after crashing during the firmware updates and is unusable.