I found it in message from Vera:
1. Plug the U disk into your PC and copy the attached file “xxxxxxxxx.atos” to the root catalog of the U flash disk. After finish copying, unplug the U flash disk from PC and then insert U flash disk into the U-disk interface of AT8612.
2. Press the numeric key "5" and ”8” at the same time, please don't release the number key, then start AT8612, then the instrument screen will appear Program burn page.
3. Press numeric key to select according to instruction on the screen, then press <enter>, and then wait for the process of update.