How do I perform a factory reset on the CXA61/CXA81?

The CXA61/CXA81 can be restored to its factory settings by following the steps below: 

1. Whilst the CXA is in standby mode, press and hold the speaker A/B button;  

2. Then when the A/B lights flash, press D1, D3, USB, D2 in a U shape sequence.