The TI SimpleLink Wi-Fi SDK provides example code for the use of Dropbox or GITHUB to perform Over the Air (OTA) updates. However, TI cannot guarantee the operation of these 3rd party services for long term use. Recent changes by Dropbox have highlighted that connection issues may occur when using the OTA library from the SDK to connect to the Dropbox server. Details of the specific Dropbox circumstances are provided below.
It is important to note that Dropbox has confirmed an August 2021 timeframe for permanently updating their server certificate handling. Customers needing future OTA compatibility with the Dropbox service will need to update the SimpleLink Wi-Fi OTA library by using SDK 5.10 and update the Dropbox root CA certificates before August. The planned release timeframe for SDK 5.10 is the end of 1Q 2021. Please see update in below post.
The OTA update procedure involves connecting to 2 servers:
- The Dropbox OTA (CDN) server for authenticating and granting permission to access folders where the image is located
- The Dropbox file server itself to load the image
Historically, Dropbox used the same root of trust for the 2 servers, which allowed customers to set only one root CA to verify and enable the connection with the OTA library.
Last week Dropbox updated the certificate handling to require unique certificates per server. This caused connection failures as described above. When notified of the issues this caused, Dropbox willingly agreed to revert back to the original certificate handling until August 2021 to allow an adjustment period for manufacturers. The OTA library modifications planned for SDK 5.10 will enable support for connecting to a CDN server and a file server when they use different root CAs. Customers should update their initial programming image and devices in the field to use the new OTA library and updated Dropbox root CA certificates to ensure future OTA functionality. Please see update in below post.