I was told by a Sharp repair technician it's nothing more than flash of the firmware that fixes the ARC disconnect problem, and no it can't be done at home.
My first SB-60 failed completely, one day it just stopped working. Just dead, would not turn on at all.
The replacement SB-60 was shipped new in the box and it developed the ARC disconnect issue right at 30 days.
It will be interesting if they just flash your firmware and send back your original SB-60.
Do you have S/N on the unit you sent back?
I really liked the SB-60 but it looks like they have software issues with the first batch.
Keep us updated, I may take another swing at the big sound bar if they work out the bugs.