Apparently, there are 2 reported issues now, one of which the bricks the Axe.
I am one of them and I am still using 5.03 even though in trying to adjust the FC-6 screen brightness I lost the main display....so I am using it a bit blind as to what patch I am on but it is working flawlessly otherwise.
I suspect in coding something ...they messed up something else...probably fixed shortly...fingers crossed.