Sony SRS-ZR7 Help Manual page 233

Hint
The number of flashes of the UPDATE indicator will change according to the update's progress. The UPDATE indicator flashes four times at first,
and decreases by one flash, then turns off when the updating is completed. Do not turn the speaker off during the update.
Note
When you update using a USB flash drive, the update cannot be stopped. If the USB flash drive is removed or the speaker is unplugged from the
power supply during the update, the speaker will malfunction.
Updating normally takes 3 to 10 minutes.
Do not operate the speaker during an update. Also, keep the speaker connected to the power supply and network while updating.
4-592-259-11(1) Copyright 2016 Sony Corporation
217