That sounds like the standard behavior of areca controllers when they have disk cache which was not written to the disks. Of course the hanging after boot is not normal.

When it is 'Waiting for Firmware' it will typically write disk cache to the drives which is why it can sit on this screen longer than normal (I have seen disks show major disk activity for 5+ seconds while this happens).

Its very rare that I see it totally hang on that unless there is a problem with one of the drive in the array and the controller is unable to write the data to the drive during array initialization. The few times I have seen this one of the drive had to be pulled shortly after due to errors.