Thanks for reaching out to us and we're sorry about this issue! We recently realized that there is a bug with v4 firmware that makes it impossible to upgrade firmware version from v4. This is clearly a huge issue and we apologize for the oversight on our part that led to this error.
One way to get around this is to factory reset your Wi-Fi AP, which should downgrade the firmware as well, then upgrade from there.
To factory reset your Wi-Fi Access Point:
1. Find a straight pin or unbend a paperclip.
2. Delete the Wi-Fi Access Point from your account.
3. Unplug your Wi-Fi Access Point and insert your tool into the pinhole at the side of the Wi-Fi Access Point. Press the reset button inside.
4. Keep the reset button pressed, plug in your Wi-Fi Access Point again, then continue holding for 60 seconds after the Wi-Fi Access Point has power. Release once the Wi-Fi Access Point light changes.
5. IMPORTANT: Do not unplug or attempt to re-add the Wi-Fi Access Point until the light turns a steady red.
6. Once your Wi-Fi Access Point has been reset, you can register it to your account again. The firmware version will return to the version your Wi-Fi module was originally shipped with.
You can update the firmware once the Wi-Fi Access Point is successfully registered to your account. We're hopeful that this will resolve the issue you experienced. If the issue persists after trying the above, please email firstname.lastname@example.org with your Sesame email address and order number so we can process a replacement unit for your Wi-Fi module. Thank you so much and once again, we apologize for the inconvenience caused! - CANDY HOUSE