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 GITHUB have highlighted that connection issues may occur when using the OTA library from the SDK to connect to the GITHUB server. Details of the specific GITHUB circumstances are provided below.
It is important to note that GITHUB has could not confirm the timeframe for permanently updating their server certificate handling. Customers needing future OTA compatibility with the GITHUB service will need to update the SimpleLink Wi-Fi OTA library by using SDK 5.10 and update the GITHUB root CA certificates as soon as possibe. 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 GITHUB OTA (api.github.com) server for authenticating and granting permission to access folders where the image is located
- The GITHUB file server itself to load the image
Historically, GITHUB 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.
Recently GITHUB updated the certificate handling to require unique certificates per server (the “api.github.com” now requires the DigiCert Global Root CA). This caused connection failures as described above. When notified of the issues this caused, GITHUB willingly agreed to revert back to the original certificate handling as a temporary 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 GITHUB root CA certificates to ensure future OTA functionality. Please see update in below post.