(1) Download the latest Sentry Video Doorbell firmware here.
(2) Unzip the zip file and copy the file named “app” to the root of a micro SD card (please also make sure that the SD card is formatted to FAT32).
(3) Disconnect the Sentry video doorbell from power and insert the micro SD card into the Sentry SD card slot (where is the SD card slot?). If Sentry is installed, you will need to unmount it from the base plate.
(4) Power up Sentry again (please use a 5V 2A micro USB adapter). Immediately (within 1-2 seconds) after the Sentry video doorbell is connected to power, long-press the RESET button at the back of the doorbell body (between the two terminal screws) for approximately 3 seconds. You should see the doorbell indicator light flashing fast in full circle.
(4) Wait for about 2 minutes till the flashing light disappears. If your Sentry doorbell was not set up previously, you will hear “system startup” and “waiting for connection”; if your Sentry doorbell was already set up, it will restart, and you can then check its firmware version in Sentry settings.
(5) Remember to unmount the SD card and delete the firmware update file before using it on Sentry again.